Change search
Refine search result
1 - 27 of 27
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ahuja, D.
    et al.
    Synthesis and Solid State Pharmaceutical Centre, Department of Chemical Sciences, Bernal Institute, University of Limerick, Castletroy, Co., Limerick, Ireland.
    Bannigan, P.
    Synthesis and Solid State Pharmaceutical Centre, Department of Chemical Sciences, Bernal Institute, University of Limerick, Castletroy, Co., Limerick, Ireland.
    Rasmuson, Åke Christoffer
    Synthesis and Solid State Pharmaceutical Centre, Department of Chemical Sciences, Bernal Institute, University of Limerick, Castletroy, Co., Limerick, Ireland.
    Study of three solvates of sulfamethazine2017In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 19, no 43, p. 6481-6488Article in journal (Refereed)
    Abstract [en]

    Three novel solvates of sulfamethazine (SMT), an anti-microbial and anti-infective sulfonamide drug with the solvents-dimethylacetamide, dimethylformamide and dimethyl sulfoxide have been identified and characterized by analytical techniques including differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and Raman spectroscopy. All three are 1:1 solvates. Crystal structure analysis revealed N-H-O type intermolecular hydrogen bonding interactions between SMT and the solvent imparting stability to the solvate structure. Thermal analysis measurements for the stoichiometry of the solvates were in good agreement with the single crystal data. The solubility of the solvates in their respective solvents at 25 °C has been determined. © 2017 The Royal Society of Chemistry.

  • 2.
    Ahuja, Dipali
    et al.
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Svärd, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena. Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena. Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Investigation of solid-liquid phase diagrams of the sulfamethazine-salicylic acid co-crystal2019In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 21, no 18, p. 2863-2874Article in journal (Refereed)
    Abstract [en]

    The influence of temperature and solvent on the solid-liquid phase diagram of the 1 : 1 sulfamethazinesalicylic acid co-crystal has been investigated. Ternary phase diagrams of this co-crystal system have been constructed in three solvents: methanol, acetonitrile and a 7 : 3 (v/v) dimethylsulfoxide-methanol mixture, at three temperatures. The system exhibits congruent dissolution in acetonitrile and the co-crystal solubility has been determined by a gravimetric technique. The Gibbs energy of co-crystal formation from the respective solid components has been estimated from solubility data, together with the corresponding enthalpic and entropic component terms. The Gibbs energy of formation ranges from -5.7 to -7.7 kJ mol -1, with the stability increasing with temperature. In methanol and the DMSO-methanol mixture, the co-crystal dissolves incongruently. It is shown that the solubility ratio of the pure components cannot be used to predict with confidence whether the co-crystal will dissolve congruently or incongruently. The size of the region where the co-crystal is the only stable solid phase is inversely related to the pure component solubility ratio of salicylic acid and sulfamethazine.

  • 3. Chen, Song
    et al.
    Grandfield, Kathryn
    Yu, Shun
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Engqvist, Håkan
    Xia, Wei
    Synthesis of calcium phosphate crystals with thin nacreous structure2016In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 18, no 6, p. 1064-1069Article in journal (Refereed)
    Abstract [en]

    Nacre-like structures have attracted great interest in recent years due to their outstanding toughness, stiffness and impact resistance. However, there is a challenge associated with engineering nacre-like calcium phosphate crystals. In this study, thin nacreous-like monetite sheets were synthesized in solutions guided by a surfactant. The influence of temperature, initial pH, Ca/P ratio, stirring time and the concentration of cetyltrimethylammonium bromide (CTAB) on the nacre-like structure has been studied. Findings showed that a nacre-like structure could only be formed at a high temperature (90 °C), high initial pH (11), sufficient stirring time (3 h), and under the presence of CTAB. A small-angle X-ray scattering experiment carried out at a synchrotron radiation facility showed that the distance between nanolayers was around 2.6 nm and TEM confirmed the fine sheet-like structure. The mechanism of the formation the nacre-like structure and its characterization were discussed.

  • 4. Cheuk, Dominic
    et al.
    Svärd, Michael
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena. University of Limerick, Ireland.
    Seaton, Colin
    McArdle, Patrick
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena. University of Limerick, Ireland.
    Investigation into solid and solution properties of quinizarin2015In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 17, no 21, p. 3985-3997Article in journal (Refereed)
    Abstract [en]

    Polymorphism, crystal shape and solubility of 1,4-dihydroxyanthraquinone (quinizarin) have been investigated in acetic acid, acetone, acetonitrile, n-butanol and toluene. The solubility of FI and FII from 20 degrees C to 45 degrees C has been determined by a gravimetric method. By slow evaporation, pure FI was obtained from n-butanol and toluene, pure FII was obtained from acetone, while either a mixture of the two forms or pure FI was obtained from acetic acid and acetonitrile. Slurry conversion experiments have established an enantiotropic relationship between the two polymorphs and that the commercially available FI is actually a metastable polymorph of quinizarin under ambient conditions. However, in the absence of FII, FI is kinetically stable for many days over the temperature range and in the solvents investigated. FI and FII have been characterized by infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), transmission and ordinary powder X-ray diffraction (PXRD) at different temperatures. The crystal structure of FII has been determined by single-crystal XRD. DSC and high-temperature PXRD have shown that both FI and FII will transform into a not previously reported hightemperature form (FIII) around 185 degrees C before this form melts at 200-202 degrees C. By indexing FIII PXRD data, a triclinic P (1) over bar cell was assigned to FIII. The solubility of quinizarin FI and FII in the pure organic solvents used in the present work is below 2.5% by weight and decreases in the order: toluene, acetone, acetic acid, acetonitrile and n-butanol. The crystal shapes obtained in different solvents range from thin rods to flat plates or very flat leaves, with no clear principal difference observed between FI and FII.

  • 5. Croker, D. M.
    et al.
    Davey, R. J.
    Rasmuson, Åke Christoffer
    Univ Limerick, Mat & Surface Sci Inst, Dept Chem & Environm Sci.
    Seaton, C. C.
    Solution mediated phase transformations between co-crystals2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 11, p. 2044-2047Article in journal (Refereed)
    Abstract [en]

    A solution mediated transformation between two co-crystal phases has been observed for the p-toluensulfonamide-triphenylphosphine oxide co-crystal system. This system has two known co-crystals with 1 : 1 and 3 : 2 stoichiometry respectively, and the ternary phase diagram (TPD) for the system has been determined in acetonitrile previously. By manipulating the solution composition in this solvent to a region of the TPD where the 1 : 1 co-crystal is stable, the 3 : 2 co-crystal could be observed to convert to the 1 : 1 co-crystal. The corresponding transformation was true for the 1 : 1 co-crystal in a region of the TPD where the 3 : 2 co-crystal is stable; the 1 : 1 co-crystal converted to the 3 : 2 co-crystal.

  • 6. Gebauer, D.
    et al.
    Liu, X.
    Aziz, B.
    Hedin, N.
    Zhao, Zhe
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Porous tablets of crystalline calcium carbonate via sintering of amorphous nanoparticles2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 6, p. 1257-1263Article in journal (Refereed)
    Abstract [en]

    Porous tablets of crystalline calcium carbonate were formed upon sintering of a precursor powder of amorphous calcium carbonate (ACC) under compressive stress (20 MPa) at relatively low temperatures (120-400 °C), induced by pulsed direct currents. Infrared spectroscopy ascertained the amorphous nature of the precursor powders. At temperatures of 120-350 °C and rates of temperature increase of 20-100 °C min-1, the nanoparticles of ACC transformed into crystallites of mainly aragonite, which is generally difficult to achieve using wet-chemicals under kinetic control. The amorphous precursor particles (∼10 nm) transformed into crystallites (∼30-50 nm) during sintering. Consistently, the specific surface areas of 140-160 m2 g-1 for the precursor particles were reduced to 10-20 m2 g-1 for the porous tablets. The porous network within the tablets consisted of fused aragonite and vaterite particles in a ratio of ∼80:20. The fraction of aragonite to vaterite was invariant to the temperature and rate of temperature change used. The particle size increased only to a small amount on an increased rate of temperature change. At temperatures above 400 °C, porous tablets of calcite formed. The later transformation was under thermodynamic control, and led to a minor reduction of the specific surface area. The size of the crystallites remained small and the transformation to calcite appeared to be a solid-state transformation. Porous, template- and binder-free tablets of calcium carbonate could find applications in for example, biology or water treatment.

  • 7.
    Hjorth, Timothy
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Svärd, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Univ Limerick, Dept Chem & Environm Sci, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Castletroy, Ireland..
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Univ Limerick, Dept Chem & Environm Sci, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Castletroy, Ireland..
    Rationalising crystal nucleation of organic molecules in solution using artificial neural networks2019In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 21, no 3, p. 449-461Article in journal (Refereed)
    Abstract [en]

    In this study, the method of artificial neural networks (ANNs) is applied to analyse the effect of various solute, solvent, and solution properties on the difficulty of primary nucleation, without bias towards any particular nucleation theory. Sets of ANN models are developed and fitted to data for 36 binary systems of 9 organic solutes in 11 solvents, using Bayesian regularisation without early stopping and 6-fold cross validation. An initial model set with 21 input parameters is developed and analysed. A refined model set with 10 input parameters is then evaluated, with an overall improvement in accuracy. The results indicate partial qualitative consistency between the ANN models and the classical nucleation theory (CNT), with the nucleation difficulty increasing with an increase in mass transport resistance and a reduction in solubility. Notably, some parameters not included in CNT, including solute molecule bond rotational flexibility, the entropy of melting of the solute, and intermolecular interactions, also exhibit explanatory importance and significant qualitative effect relationships. A high entropy of melting and solute bond rotational flexibility increase the nucleation difficulty. Stronger solute-solute or solvent-solvent interactions are correlated with a facilitated nucleation, which is reasonable in the context of desolvation. A dissimilarity between solute and solvent hydrophobicities is connected with an easier nucleation.

  • 8. Jalilian, E.
    et al.
    Liao, R.
    Himo, F.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Lidin, S.
    Flourescence properties of the (Cu 4I6)2-- cluster2011In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 13, p. 4729-4734Article in journal (Refereed)
    Abstract [en]

    Two new solvates were prepared in the system Cu(I)I using a solvolysis reaction. The structures for both of them were solved by X-ray crystallography, showing that they constitute two modifications of the same compound with the net formula [Cu4I6](P(C6H5)4)2·2OC(CH3)2. Both types of crystals show vivid fluorescence when exposed to UV light. The formation of the first modification (I) seems to be preferred by kinetics and on ageing in the mother liquor it converts to modification (II). The Cu positions in (I) are disordered while those in (II) are fully ordered. The luminescent properties of both crystals were characterized using a confocal microscope and an excitation wavelength of 405 nm, resulting in fluorescence spectra with the intensities of 1.22 and 0.52 relative to the reference (fluorescein 10 µM). Density functional theory calculations on the ordered Cu4I62− core of modification (II) show that the de-excitation from LUMO to HOMO is responsible for the luminescence. The calculated emission spectrum has a maximum at 531 nm in good agreement with the results from confocal microscopy.

  • 9. Jalilian, Ehsan
    et al.
    Liao, Rong-Zhen
    Himo, Fahmi
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Laurell, Fredrik
    Lidin, Sven
    Luminescence properties of the Cu4I62- cluster2011In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 13, no 14, p. 4729-4734Article in journal (Refereed)
    Abstract [en]

    Two new solvates were prepared in the system Cu(I) I using a solvolysis reaction. The structures for both of them were solved by X-ray crystallography, showing that they constitute two modifications of the same compound with the net formula [Cu4I6](P(C6H5)(4))(2)center dot 2OC(CH3)(2). Both types of crystals show vivid fluorescence when exposed to UV light. The formation of the first modification (I) seems to be preferred by kinetics and on ageing in the mother liquor it converts to modification (II). The Cu positions in (I) are disordered while those in (II) are fully ordered. The luminescent properties of both crystals were characterized using a confocal microscope and an excitation wavelength of 405 nm, resulting in fluorescence spectra with the intensities of 1.22 and 0.52 relative to the reference (fluorescein 10 mu M). Density functional theory calculations on the ordered Cu4I62- core of modification (II) show that the de-excitation from LUMO to HOMO is responsible for the luminescence. The calculated emission spectrum has a maximum at 531 nm in good agreement with the results from confocal microscopy.

  • 10.
    Jaramillo-Fernandez, Juliana
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Chavez-Angel, Emigdio
    Sanatinia, Reza
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. Harvard Univ, USA.
    Kataria, Himanshu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. IRnova AB, Sweden.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Sotomayor-Torres, Clivia M.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. CSIC, Spain; Barcelona Inst Sci & Technol, Spain; ICREA, Spain.
    Thermal conductivity of epitaxially grown InP: experiment and simulation2017In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 19, no 14, p. 1879-1887Article in journal (Refereed)
    Abstract [en]

    The integration of III-V optoelectronic devices on silicon is confronted with the challenge of heat dissipation for reliable and stable operation. A thorough understanding and characterization of thermal transport is paramount for improved designs of, for example, viable III-V light sources on silicon. In this work, the thermal conductivity of heteroepitaxial laterally overgrown InP layers on silicon is experimentally investigated using microRaman thermometry. By examining InP mesa-like structures grown from trenches defined by a SiO2 mask, we found that the thermal conductivity decreases by about one third, compared to the bulk thermal conductivity of InP, with decreasing width from 400 to 250 nm. The high thermal conductivity of InP grown from 400 nm trenches was attributed to the lower defect density as the InP micro crystal becomes thicker. In this case, the thermal transport is dominated by phonon-phonon interactions as in a low defect-density monocrystalline bulk material, whereas for thinner InP layers grown from narrower trenches, the heat transfer is dominated by phonon scattering at the extended defects and InP/SiO2 interface. In addition to the nominally undoped sample, sulfur-doped (1 x 10(18) cm(-3)) InP grown on Si was also studied. For the narrower doped InP microcrystals, the thermal conductivity decreased by a factor of two compared to the bulk value. Sources of errors in the thermal conductivity measurements are discussed. The experimental temperature rise was successfully simulated by the heat diffusion equation using the FEM.

  • 11. Lai, Xiaojun
    et al.
    Roberts, Kevin J.
    Svensson, Joakim
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    White, Graeme
    Reaction calorimetric analysis of batch cooling crystallization processes: studies of urea in supersaturated water-methanol solutions2011In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 13, no 7, p. 2505-2510Article in journal (Refereed)
    Abstract [en]

    A thermal energy balance model is developed for the monitoring of batch cooling crystallization processes and applied to the analysis of the crystallization of urea from an 80% methanol and 20% water solution using a 2-litre batch reaction calorimeter operating over a range of cooling rate from 0.1 degrees C min(-1) to 0.5 degrees C min(-1). Detailed calibrations and measurements to determine the parameters needed for the energy and material balance calculation of crystallization reveal the overall heat transfer coefficient, the solution heat capacity, the solubility, the metastable zone width, and the molar enthalpy of crystallization. The instantaneous enthalpy evolved as a result of nucleation and subsequent crystal growth are determined via applying the energy balance model. The rates of the nucleation and crystal growth and the solution supersaturation during the crystallization processes are subsequently calculated. For a typical crystallization process at 0.25 degrees C min(-1) cooling rate, the peak value of crystallization rate mainly due to the nucleation was approximately 30 g min(-1), and thereafter the growth rate slowly decreased from 7 g min(-1) and 3 g min(-1) following the change of solution supersaturation. The influence of seeding is also analyzed and the generic appliables of this approach is discussed.

  • 12. Li, Ping
    et al.
    Wang, Mei
    Chen, Lin
    Wang, Ning
    Zhang, Tingting
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Supramolecular self-assembly of a 2Fe2S complex with a hydrophilic phosphine ligand2008In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 10, no 3, p. 267-269Article in journal (Refereed)
    Abstract [en]

    A diiron complex [{(mu-SCH2)(2)CH2}{Fe-2(CO)(5)P(CH2OH)(3)}] was prepared as a biomimic of the [2Fe2S] subunit in the active site of [FeFe] hydrogenases, which appears as a supramolecular self-assembly in the solid state with O-H center dot center dot center dot O hydrogen bonds forming two-dimensional arrays with alternately right- and left-handed helical O-H center dot center dot center dot O-H chains.

  • 13. Lynch, A.
    et al.
    Verma, V.
    Zeglinski, J.
    Bannigan, P.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Synthesis and Solid State Pharmaceutical Centre, Bernal Institute, Department of Chemical Sciences, University of Limerick, Limerick, Ireland.
    Face indexing and shape analysis of salicylamide crystals grown in different solvents2019In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 21, no 16, p. 2648-2659Article in journal (Refereed)
    Abstract [en]

    The effect of solvent on salicylamide's crystal habit was investigated. Crystals grown experimentally in acetone, acetonitrile and methanol matched the attachment energy predicted rectangle plate vacuum habit. However, in ethyl acetate irregular hexagonal plate crystals form. This change in habit was found to be caused by the stunted growth of specific crystal faces during the crystallisation process. Single crystal and powder X-ray diffraction was carried out to rule out the possibility of a new polymorph. Given no new polymorphs were discovered, the changing habit makes face indexing of experimentally grown crystals difficult. A combination of experimental and modelling prediction tools was employed for the face indexing process. The interfacial angle between faces combined with preferred orientation P-XRD was found to be the most accurate and reliable method leading to successful identification of each salicylamide crystal face. The surface chemistry of each face was examined on a molecular level with insights into the possible growth attachment sites being made. It is deduced that ethyl acetate is adsorbed more strongly on the faces, the increased size of which, can explain the shape change.

  • 14. Mealey, Donal
    et al.
    Croker, Denise M.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. University of Limerick, Ireland.
    Crystal nucleation of salicylic acid in organic solvents2015In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 17, no 21, p. 3961-3973Article in journal (Refereed)
    Abstract [en]

    The crystal nucleation of salicylic acid was explored in a range of solvents using induction time and metastable zone width measurements. In total 3100 experiments were performed to collect statistically valid nucleation results. The lognormal cumulative probability function provided a representative fit for both induction time and metastable zone width distributions. At equal driving force the induction time is found to increase in the order chloroform, ethyl acetate, acetonitrile, acetone, methanol and acetic acid, and this order agrees with the order of increasing interfacial energy The metastable zone width (MSZW) value (expressed as supersaturation driving force) was highest in acetic acid followed by a lower value in methanol, consistent with the induction time results. In ethyl acetate, acetonitrile and acetone the corresponding MSZW values were lower but the order among these three solvents varied depending on the cooling rate and saturation temperature. A novel format for comparing the induction time and MSZW experiments is presented. The analysis reveals that the time of nucleation in the metastable zone width experiments is also dependent on the time of transforming clusters into nuclei, and not only governed by the rate of supersaturation generation. The relative influence of this transformation time depends on the solvent and the cooling rate.

  • 15.
    Metaferia, Wondwosen
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Dev, Apurba
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Kataria, Himanshu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Junesand, Carl
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Sun, Yanting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Tommila, Juha
    Pozina, Galia
    Hultman, Lars
    Guina, Mircea
    Niemi, Tapio
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    High quality InP nanopyramidal frusta on Si2014In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 16, no 21, p. 4624-4632Article in journal (Refereed)
    Abstract [en]

    Nanosized octagonal pyramidal frusta of indium phosphide were selectively grown at circular hole openings on a silicon dioxide mask deposited on indium phosphide and indium phosphide pre-coated silicon substrates. The eight facets of the frusta were determined to be {111} and {110} truncated by a top (100) facet. The size of the top flat surface can be controlled by the diameter of the openings in the mask and the separation between them. The limited height of the frusta is attributed to kinetically controlled selective growth on the (100) top surface. Independent analyses with photoluminescence, cathodoluminescence and scanning spreading resistance measurements confirm certain doping enrichment in the frustum facets. This is understood to be due to crystallographic orientation dependent dopant incorporation. The blue shift from the respective spectra is the result of this enrichment exhibiting the Burstein-Moss effect. Very bright panchromatic cathodoluminescence images indicate that the top surfaces of the frusta are free from dislocations. The good optical and morphological quality of the nanopyramidal frusta indicates that the fabrication method is very attractive for the growth of site-, shape-, and number-controlled semiconductor quantum dot structures on silicon for nanophotonic applications.

  • 16.
    Munroe, Aina
    et al.
    Chemical and Environmental Science, University of Limerick, Ireland.
    Croker, Denise
    Chemical and Environmental Science, University of Limerick, Ireland.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Hodnett, Kieran
    Chemical and Environmental Science, University of Limerick, Ireland.
    Analysis of FII crystals of Sulphathiazole: Epitaxial growth of FII on FIV2011In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 13, no 3, p. 831-834Article in journal (Refereed)
    Abstract [en]

    This work describes the phenomenon of a less stable polymorph wedged as a middle layer in a more stable polymorph of sulfathiazole. Isolation of the pure FII polymorph of sulfathiazole consistently yielded crystals with a distinctive middle layer. Raman spectroscopy and X-ray diffraction have identified this middle layer as another polymorph of sulfathiazole, namely FIV. The solubilities of FII and FIV sulfathiazole are almost identical, with FIV slightly more soluble. It is thought that this causes FIV to nucleate first, followed by the epitaxial growth of FII. A morphological examination of the crystals demonstrated that the (100) face of the FII crystal matches the (101) face of the FIV crystal. It is proposed that the similarity of these faces supports the epitaxial growth of the FII polymorph on the surface of the FIV polymorph.

  • 17. Nordström, Fredrik L.
    et al.
    Svärd, Michael
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Primary nucleation of salicylamide: the influence of process conditions and solvent on the metastable zone width2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 36, p. 7285-7297Article in journal (Refereed)
    Abstract [en]

    The onset of nucleation of salicylamide in organic solvents has been measured for a total of 2911 nucleation experiments at a constant cooling rate. The experiments are divided into series of different experimental conditions and for each series, the mean values and distributions of the nucleation events have been recorded. Generally, a significant spread in the onset of nucleation among identical repeated experiments was observed. The solvent and the cooling rate were found to be the factors exerting the greatest influence on the onset of nucleation, whereas the expected effects of the solution volume and the saturation temperature were largely absent. A correlation is observed between the supersaturation ratio at the average onset of nucleation and a group of parameters extracted from the pre-exponential factor in the classical nucleation rate equation, which is in agreement with the concept that a higher attachment frequency facilitates nucleation. It is also found that there can be a profound difference in the metastable zone width between experiments in open and closed crystallizers.

  • 18. Pena, Alexandra
    et al.
    Menaert, Bertrand
    Debray, Jerome
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. KTH, School of Engineering Sciences (SCI), Physics.
    Boulanger, Benoit
    Stability of the polar faces in KTiOPO4 crystalline layers grown by liquid phase epitaxy2018In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 20, no 46, p. 7502-7506Article in journal (Refereed)
    Abstract [en]

    The polar faces, (001) and (001), of the ferroelectric KTiOPO4 crystal are not equivalent by symmetry. The stability and the growth rate of both faces have been determined by growing thick crystalline layers by liquid phase epitaxy onto oriented crystalline commercial KTiOPO4 slabs. Growth solutions with different molar compositions in the system KTiOPO4-KPO3-KF and different supersaturation degrees end up with the same result. Whereas the (00 (1) over bar) faces are stable under all the experimental conditions used, the (001) ones are not stable and turn into (00 (1) over bar) faces. Head-to-head domains oriented along the [010] axis at vertical bar 7 +/- 1 degrees vertical bar to the [001] axis propagate from the (001) surface of the seed to the as-grown crystalline layers. The final epitaxies obtained by this process show two (00 (1) over bar) polar end faces; so a twin-crystal along the c direction was grown.

  • 19.
    Soroka, Inna L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Tarakina, Nadezda V.
    Korzhavyi, Pavel A.
    Stepanenko, Vladimir
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Effect of synthesis temperature on the morphology and stability of copper(I) hydride nanoparticles2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 42, p. 8450-8460Article in journal (Refereed)
    Abstract [en]

    The effect of synthesis temperature on the morphology and stability of copper(I) hydride nanoparticles is studied. Monovalent copper hydride is obtained by reduction of Cu2+ sulfate with hypophosphorous acid at temperatures ranging from 45 degrees C to 75 degrees C. The CuH nanoparticles that formed have the shape of desert roses and are found to be very porous. The lattice parameter, size, and morphology of these nanoparticles depend on the synthesis temperature. CuH is a metastable compound. In air under ambient conditions, it first decomposes into copper metal and hydrogen gas and then the copper oxidizes. The copper particles that are left after the decomposition of copper(I) hydride in air have the same desert-rose morphology as the CuH nanoparticles. The copper particles with desert-rose shapes are observed for the first time. Copper(I) hydride decomposes slower in an aqueous environment than in air to form copper(I) oxide as the final product through formation of hydrated copper(I) hydroxide as an intermediate phase. The retarded decomposition of CuH in water may be explained by the formation of a protective CuOH center dot H2O layer on the surface of copper(I) hydride.

  • 20. Sun, Yan-Ting
    et al.
    Kataria, Himanshu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Realization of atomically abrupt InP/Si heterojunction and dislocationreduction via corrugated epitaxial lateral overgrowthIn: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033Article in journal (Other academic)
  • 21.
    Svärd, Michael
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Krishna, Gamidi Rama
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Synthesis, crystallisation and thermodynamics of two polymorphs of a new derivative of meglumine: 1-(2,2,3-trimethyl-1,3-oxazolidin-5-yl)-butane-1,2,3,4-tetrol2018In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 20, no 1, p. 88-95Article in journal (Refereed)
    Abstract [en]

    A new compound, 1-(2,2,3-trimethyl-1,3-oxazolidin-5-yl)-butane-1,2,3,4-tetrol, has been discovered, described, and its crystal polymorphism investigated. The crystal structures of two polymorphs have been solved with single-crystal X-ray diffraction. The molecule is chiral with four stereo centers, and both polymorphs crystallise in the non-centrosymmetric orthorhombic, chiral P2(1)2(1)2(1) space group, with one molecule in the asymmetric unit. In both structures the molecules are arranged three dimensionally in an interlocked manner, stabilized by strong O-H center dot center dot center dot O and weaker C-H center dot center dot center dot O and pi center dot center dot center dot pi interactions. The polymorphs have been characterized by X-ray powder diffraction (XRPD) and infrared spectroscopy (IR). The thermodynamic stability relationship between the polymorphs from 280 K up to the melting points has been quantitatively determined by differential scanning calorimetry (DSC), through measurement of melting points, heats of fusion, and heat capacities of the solid phases and the supercooled melt. It is established that the relationship is most likely monotropic, with one polymorph (FI) stable throughout the entire evaluated temperature range. The stability relationship at room temperature has been confirmed by a slurry conversion experiment.

  • 22.
    Svärd, Michael
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Nordström, Fredrik L.
    Hoffmann, Eva-Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Aziz, Baroz
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena. Department of Chemical and Environmental Science, Solid State Pharmaceutical Cluster, Materials and Surface Science Institute, University of Limerick, Ireland .
    Thermodynamics and nucleation of the enantiotropic compound p-aminobenzoic acid2013In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 15, no 25, p. 5020-5031Article in journal (Refereed)
    Abstract [en]

    In this work, the thermodynamic interrelationship of the two known polymorphs of p-aminobenzoic acid has been explored, and primary nucleation in different organic solvents investigated. The solubility of both polymorphs in several solvents at different temperatures has been determined and the isobaric solid-state heat capacities have been measured by DSC. The transition temperature below which form α is metastable is estimated to be 16°C by interpolation of solubility data and the melting temperature of form β is estimated to be 140°C by extrapolation of solubility data. Using experimental calorimetry and solubility data the thermodynamic stability relationship between the two polymorphs has been estimated at room temperature to the melting point. At the transition temperature, the estimated enthalpy difference between the polymorphs is 2.84 kJ mol-1 and the entropy difference is 9.80 J mol-1 K-1. At the estimated melting point of form β the difference in Gibbs free energy and enthalpy is 1.6 kJ mol-1 and 5.0 kJ mol-1, respectively. It is found that the entropic contribution to the free energy difference is relatively high, which explains the unusually low transition temperature. A total of 330 nucleation experiments have been performed, with constant cooling rate in three different solvents and with different saturation temperatures, and multiple experiments have been carried out for each set of conditions in order to obtain statistically significant results. All performed experiments resulted in the crystallization of the high-temperature stable α-polymorph, which is kinetically favoured under all evaluated experimental conditions. The thermodynamic driving force required for nucleation is found to depend chiefly on the solvent, and to be inversely correlated to both solvent polarity and to solubility.

  • 23.
    Wang, Jing
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Guo, Peng
    Guo, Qiangsheng
    Jönsson, Pär G.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Zhao, Zhe
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Ceramics.
    Fabrication of novel g-C3N4/nanocage ZnS composites with enhanced photocatalytic activities under visible light irradiation2014In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 16, no 21, p. 4485-4492Article in journal (Refereed)
    Abstract [en]

    In order to develop efficient visible light-driven photocatalysts for environmental applications, novel g-C3N4/nanocage ZnS composites have been successfully fabricated via an anion exchange route using ZIF-8 as a self-sacrificing template. The as-prepared g-C3N4/ZnS composites were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy and photoluminescence. In addition, the photocatalytic oxidation of organic contaminants in aqueous solution was investigated with the g-C3N4/ZnS composite system under visible light irradiation by using rhodamine B as a model compound. The results indicate that the g-C3N4/ZnS composite photocatalysts show higher photocatalytic activity than the single component (pure g-C3N4 or ZnS). More specifically, the optimum photocatalytic activity of the g-C3N4/ZnS composite was achieved with a weight ratio of 6 : 1, which is as high as 37.8 and 2.8 times those of individual ZnS and g-C3N4 under visible light irradiation. The enhanced photocatalytic activity of g-C3N4/ZnS is mainly attributed to an efficient electron-hole separation at the interface of the two semiconductors, as determined by photoluminescence spectroscopy. Moreover, it is observed that. O-2 is the main active species in the photocatalytic oxidation of RhB solution using a g-C3N4/nanocage ZnS composite.

  • 24.
    Yang, Huaiyu
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. Univ Strathclyde, Scotland.
    Relation between metastable zone width and induction time of butyl paraben in ethanol2015In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 17, no 3, p. 577-586Article in journal (Refereed)
    Abstract [en]

    A relation between induction time and metastable zone width in cooling crystallization has been developed based on Classical Nucleation Theory, and an interpretation equation of this relation has been used to extrapolate metastable zone width from the induction time results in homogenous primary nucleation. The metastable zone width is determined by the interfacial energy and the pre-exponential factor. 440 metastable zone experiments of butyl paraben in ethanol at five different cooling rates have been performed. The experimental metastable zone widths of butyl paraben in ethanol are fairly close to those extrapolated from the induction time results. The positive correlation between the cooling rate and the experimental metastable zone width is in good agreement with the interpretation equation, from which the relations between stirring rate, saturation temperature and volume of solution with estimated metastable zone width have been investigated.

  • 25. Zaldua, N.
    et al.
    Mugica, A.
    Zubitur, M.
    Iturrospe, A.
    Arbe, A.
    Re, Giada Lo
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Raquez, J. -M
    Dubois, P.
    Müller, A. J.
    The role of PLLA-g-montmorillonite nanohybrids in the acceleration of the crystallization rate of a commercial PLA2016In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 18, no 48, p. 9334-9344Article in journal (Refereed)
    Abstract [en]

    Employing the hydroxyl groups on the surface of Cloisite® 30B montmorillonite (Cl30B), the ring-opening polymerization of l-lactide was performed with a metal-free catalyst to yield a PLLA-g-Cl30B nanohybrid with low Mn grafted PLLA chains (i.e., 9 kg mol-1). This nanohybrid was then melt mixed with PLA 4032D from NatureWorks, which is a slow-crystallizing PLA as it contains 2% d-isomers and has a high Mn value (i.e., 123 kg mol-1). The samples were characterized by TEM, WAXS, SAXS, DSC and Polarized Light Optical Microscopy (PLOM) in order to study their crystallization kinetics in depth. The dispersion of the nanoclay was excellent and much better in the PLA/PLLA-g-Cl30B nanocomposites in comparison to PLA/Cl30B blends prepared as reference. In order to ascertain the role of the nanoclay, analogue PLA/PLLA blends without Cl30B were also prepared. The spherulitic crystallization kinetics from the melt was determined for all samples. The growth rate of neat PLA was accelerated approximately 3 times by incorporating the PLLA-g-Cl30B nanohybrid with an inorganic content of 5%. The overall crystallization kinetics from the glassy state of PLA was also accelerated in a similar way by the nanohybrid addition. Nevertheless, the PLA/PLLA blends crystallized even faster indicating that the dominant effect that causes the acceleration of the crystallization of PLA is the plasticization of PLA by the low Mn PLLA molecules. The changes in Tg of PLA also support this explanation. In the case of the PLA/PLLA-g-Cl30B nanocomposites, even though the plasticizing effect of the PLLA chains still dominates, their action is counterbalanced by their tethering on one end, as they are grafted to the surface of the exfoliated clay nanoplatelets.

  • 26.
    Zhang, Shuo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Chen, Hong
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena. University of Limerick, Ireland.
    Thermodynamics and crystallization of a theophylline-salicylic acid cocrystal2015In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 17, no 22, p. 4125-4135Article in journal (Refereed)
    Abstract [en]

    A 1: 1 theophylline-salicylic acid cocrystal has been successfully prepared by slurry conversion crystallization in a 1 : 1 molar ratio slurry of theophylline and salicylic acid in chloroform. The cocrystal powder was analysed by XRD and DSC, and the cocrystal structure was determined by single crystal XRD. The cocrystal melts at 188.5 degrees C, which is between the melting points of the pure cocrystal components. Microscopy and SEM images have been taken for the cocrystals prepared by slow evaporation from ethanol, ethyl acetate, or acetonitrile. The cocrystal dissolves congruently in chloroform and the solubility is determined. Based on the solubility data for the cocrystal and the pure components, the Gibbs free energy of cocrystal formation is calculated to be -4.92 kJ mol(-1) at 30 degrees C. The cocrystal dissolves incongruently in methanol, ethanol, and acetonitrile. The ternary phase diagram of the cocrystal in acetonitrile has been determined and compared with those of theophylline-oxalic acid and theophylline-glutaric acid cocrystal systems. By proper operation of the process in the phase diagram, the theophylline-salicylic acid cocrystal can be produced by slurry conversion crystallization in acetonitrile.

  • 27.
    Zhang, Shuo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Ake C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    The theophylline-oxalic acid co-crystal system: solid phases, thermodynamics and crystallisation2012In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 14, no 14, p. 4644-4655Article in journal (Refereed)
    Abstract [en]

    The solid phases in the theophylline-oxalic acid co-crystal system have been investigated by thermal analysis techniques, X-ray diffraction analysis (XRD) and solubility measurements. The work includes the 2 : 1 co-crystal of theophylline and oxalic acid, polymorphs of theophylline, the theophylline monohydrate and solid oxalic acid. The DSC curve of the co-crystal presents two endothermic peaks, one at about 230 degrees C where the oxalic acid in the co-crystal decomposes and carbon dioxide is liberated, and another one at 279 degrees C where the remaining theophylline melts. At equilibrium with the solid co-crystal, the theophylline concentration is only 60% of the corresponding value for the pure solid theophylline. Using the solubility data, the standard Gibbs free energy of formation of the co-crystal from the pure solid phases is estimated to be approximately -6.0 kJ mole(-1). In a chloroform/methanol mixture (4 : 1 v : v) the commercial form of pure theophylline (Form II) has been observed to transform into a more stable non-solvated form (Form I). The data suggest that the polymorphs are enantiotropically related with an approximate transition temperature of 70 degrees C. The 2 : 1 theophylline-oxalic acid co-crystal can be successfully produced by cooling crystallisation in chloroform/methanol mixture (4 : 1 v : v) and by slurry conversion crystallisation also in more benign solvents.

1 - 27 of 27
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf