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• 1.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. DESY, Hamburg, Germany.. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. DESY, Hamburg, Germany..
GISAS study of spray deposited metal precursor ink on a cellulose template2019In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal (Other academic)
• 2.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. DESY, Photon Sci, Hamburg, Germany.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. DESY, Photon Sci, Hamburg, Germany.. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. DESY, Photon Sci, Hamburg, Germany..
In situ self-assembly study in bio-based thin films2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
• 3.
KTH.
KTH. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Mechanics.
Characterizing the Orientational and Network Dynamics of Polydisperse Nanofibers at the Nanoscale.Manuscript (preprint) (Other academic)
• 4.
KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
Characterizing the Orientational and Network Dynamics of Polydisperse Nanofibers on the Nanoscale2019In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 52, no 6, p. 2286-2295Article in journal (Refereed)

Polydisperse fiber networks are the basis of many natural and manufactured structures, ranging from high-performance biobased materials to components of living cells and tissues. The formation and behavior of such networks are given by fiber properties such as length and stiffness as well as the number density and fiber-fiber interactions. Studies of fiber network behavior, such as connectivity or rigidity thresholds, typically assume monodisperse fiber lengths and isotropic fiber orientation distributions, specifically for nano scale fibers, where the methods providing time-resolved measurements are limited. Using birefringence measurements in a microfluidic flow-focusing channel combined with a flow stop procedure, we here propose a methodology allowing investigations of length-dependent rotational dynamics of nanoscale polydisperse fiber suspensions, including the effects of initial nonisotropic orientation distributions. Transition from rotational mobility to rigidity at entanglement thresholds is specifically addressed for a number of nanocellulose suspensions, which are used as model nanofiber systems. The results show that the proposed method allows the characterization of the subtle interplay between Brownian diffusion and nanoparticle alignment on network dynamics.

• 5.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics.
Size-Dependent Orientational Dynamics of Brownian Nanorods2018In: ACS Macro Letters, E-ISSN 2161-1653, Vol. 7, no 8, p. 1022-1027Article in journal (Refereed)

Successful assembly of suspended nanoscale rod-like particles depends on fundamental phenomena controlling rotational and translational diffusion. Despite the significant developments in fluidic fabrication of nanostructured materials, the ability to quantify the dynamics in processing systems remains challenging. Here we demonstrate an experimental method for characterization of the orientation dynamics of nanorod suspensions in assembly flows using orientation relaxation. This relaxation, measured by birefringence and obtained after rapidly stopping the flow, is deconvoluted with an inverse Laplace transform to extract a length distribution of aligned nanorods. The methodology is illustrated using nanocelluloses as model systems, where the coupling of rotational diffusion coefficients to particle size distributions as well as flow-induced orientation mechanisms are elucidated.

• 6. Cohen, Céline
Ecole Polytech, F-91128 Palaiseau, France.
Parallelised production of fine and calibrated emulsions by coupling flow-focusing technique and partial wetting phenomenon2014In: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 17, no 5, p. 959-966Article in journal (Refereed)

The capacity of microfluidic technology to fabricate monodisperse emulsion droplets is well established. Parallelisation of droplet production is a prerequisite for using such an approach for making high-quality materials for either fundamental or industrial applications where product quantity matters. Here, we investigate the emulsification efficiency of parallelised drop generators based on a flow-focusing geometry when incorporating the role of partial wetting in order to make emulsion droplets with a diameter below 10 μm. Confinement intrinsically encountered in microsystems intensifies the role played by interfaces between liquids and solids. We thus take advantage of partial wetting to enhance the maximum confinement accessible due to liquid flow focusing. We compare the performances brought by partial wetting to more established routes such as step emulsification. We show that the step configuration and the partial wetting regime are both well suited for being parallelised and thus open the way to the production of fine and calibrated emulsions for further applications. Finally, this new route of emulsification that exploits partial wetting between the fluids and the channel walls opens possibilities to the formation of substantially smaller droplets, as required in many fields of application.

• 7. Geng, Lihong
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
Understanding the Mechanistic Behavior of Highly Charged Cellulose Nanofibers in Aqueous Systems2018In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 51, no 4, p. 1498-1506Article in journal (Refereed)

Mechanistic behavior and flow properties of cellulose nanofibers (CNFs) in aqueous systems can be described by the crowding factor and the concept of contact points, which are functions of the aspect ratio and concentration of CNF in the suspension. In this study, CNFs with a range of aspect ratio and surface charge density (380-1360 mu mol/g) were used to demonstrate this methodology. It was shown that the critical networking point of the CNF suspension, determined by rheological measurements, was consistent with the gel crowding factor, which was 16. Correlated to the crowding factor, both viscosity and modulus of the systems were found to decrease by increasing the charge density of CNF, which also affected the flocculation behavior. Interestingly, an anomalous rheological behavior was observed near the overlap concentration (0.05 wt %) of CNF, at which the crowding factor was below the gel crowding factor, and the storage modulus (G') decreased dramatically at a given frequency threshold. This behavior is discussed in relation to the breakup of the entangled flocs and network in the suspension. The analysis of the mechanistic behavior of CNF aqueous suspensions by the crowding factor provides useful insight for fabricating high-performance nanocellulose-based materials.

• 8.
Univ Tokyo, Dept Bioengn, Tokyo, Japan..
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. KTH, School of Engineering Sciences (SCI), Mechanics.
Assembly mechanism of nanostructured whey protein filaments2016In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 252Article in journal (Other academic)
• 9.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Photon Science, Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg, Germany. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Chemical Science and Engineering (CHE), Chemistry.
Flow-assisted assembly of nanostructured protein microfibers2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 6, p. 1232-1237Article in journal (Refereed)

Some of the most remarkable materials in nature are made from proteins. The properties of these materials are closely connected to the hierarchical assembly of the protein building blocks. In this perspective, amyloid-like protein nanofibrils (PNFs) have emerged as a promising foundation for the synthesis of novel bio-based materials for a variety of applications. Whereas recent advances have revealed the molecular structure of PNFs, the mechanisms associated with fibril-fibril interactions and their assembly into macroscale structures remain largely unexplored. Here, we show that whey PNFs can be assembled into microfibers using a flow-focusing approach and without the addition of plasticizers or cross-linkers. Microfocus small-angle X-ray scattering allows us to monitor the fibril orientation in the microchannel and compare the assembly processes of PNFs of distinct morphologies. We find that the strongest fiber is obtained with a sufficient balance between ordered nanostructure and fibril entanglement. The results provide insights in the behavior of protein nanostructures under laminar flow conditions and their assembly mechanism into hierarchical macroscopic structures.

• 10. Mishra, G.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
Multifunctional Mesoporous Carbon Capsules and their Robust Coatings for Encapsulation of Actives: Antimicrobial and Anti-bioadhesion Functions2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 23, p. 19371-19379Article, review/survey (Refereed)

We present the synthesis and applications of multifunctional hollow porous carbon spheres with well-ordered pore architecture and ability to encapsulate functional nanoparticles. In the present work, the applications of hollow mesoporous carbon capsules (HMCCs) are illustrated in two different contexts. In the first approach, the hollow capsule core is used to encapsulate silver nanoparticles to impart antimicrobial characteristics. It is shown that silver-loaded HMCCs (concentration ?100 μg/mL) inhibit the growth and multiplication of bacterial colonies of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) up to 96% and 83%, respectively. In the second part, the fabrication of hierarchical micro- and nanostructured superhydrophobic coatings of HMCCs (without encapsulation with silver nanoparticles) is evaluated for anti-bioadhesion properties. Studies of protein adsorption and microorganism and platelet adhesion have shown a significant reduction (up to 100%) for the HMCC-based superhydrophobic surfaces compared with the control surfaces. Therefore, this unique architecture of HMCCs and their coatings with the ability to encapsulate functional materials make them a promising candidate for a variety of applications.

• 11.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics.
Mesoporous Carbon Nanocapsules Based Coatings with Multifunctionalities2016In: Advanced Materials Interfaces, ISSN 2196-7350Article in journal (Refereed)

Multifunctional superhydrophobic coatings are fabricated based on mesoporous carbon nanocapsules (MCC) with polyvinylidene fluoride (PVDF) as a binder through a facile brush-on process. The hierarchical micro/nano structures for the coatings are optimized by the relative amount of MCC and hydrophobic PVDF polymer binder. Integration of low surface energy of polymer with micro/nano structure of the coatings is responsible for the superhydrophobicity of the surfaces. At the same time the coatings are conductive due to the MCC being a carbon-based nanoparticle. The coatings deposited on a stainless steel substrate demonstrate good abrasion resistance tested by pin-on-disk method. The hierarchically structured superhydrophobic coatings are also anti bio-fouling, showing significantly reduced bacterial adhesion (up to a 91% decrease). In addition, the superhydrophobic coatings can be applied conformally over a wide range of substrates including metal, paper, and polyester fabrics. Further, the multifunctionality for the prepared MCC-based coatings can be enhanced with the possibility to encapsulate nanoparticles inside the core of thin porous carbon shells. Surfaces coated with MCC are also found amenable to the wetting transition between superhydrophobicity to superhydrophilicity studied by the cyclic alteration of oxygen plasma treatment and thermal annealing.

• 12.
PSL Res Univ, CNRS UMR8231, ESPCI ParisTech, Lab Colloides & Mat Divises,Inst Chem Biol & Inno, F-75231 Paris, France.
Dynamics of step-emulsification: From a single to a collection of emulsion droplet generators2014In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 26, article id 082109Article in journal (Refereed)

Microfluidics has proven to be an efficient tool for making fine and calibrated emulsion droplets. The parallelization of drop makers is required for producing large amounts. Here, we investigate the generation of emulsion drops along a series of shallowmicrochannels emerging in a deep one, in other words the step-emulsification process. The dynamics of a single drop maker is first characterized as a function of interfacial tension and viscosities of both phases. The characteristic time scale of drop formation, namely, the necking time that finally sets drop size, is shown to be principally governed by the outer phase viscosity to interfacial tension ratio with a minor correction linked to the viscosity ratio. The step emulsification process experiences a transition of fragmentation regime where both the necking time and drop size suddenly raise. This transition, that corresponds to a critical period of drop formation and thus defines a maximum production rate of small droplets, is observed to be ruled by the viscosity ratio of the two phases. When drops are produced along an array of microchannels with a cross flow of the continuous phase, a configuration comparable to a one-dimensional membrane having rectangular pores, a drop boundary layer develops along the drop generators. In the small drop regime, the local dynamics of drop formation is shown to be independent on the emulsion cross flow. Moreover, we note that the development of the drop boundary layer is even beneficial to homogenize drop size along the production line. On the other hand, in the large drop regime, drop collision can trigger fragmentation and thus lead to size polydispersity.

• 13.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics.
Nanostructured Biopolymeric Materials: Hydrodynamic Assembly, Mechanical Properties and Bio-Functionalities2019Doctoral thesis, comprehensive summary (Other academic)

The need for high-end multifunctional materials from renewable resources has evolved given a rapidly increasing population and accompanying environmental concerns. Scalable assembly methods are and will be imperative in designing high-performance environmentally friendly materials, requiring new processes allowing control on all hierarchical levels. In this thesis, engineering concepts for manipulation of nanoscale components from biopolymeric resources have been applied to achieve extraordinary macroscale performance. The route chosen has been fluid-phase assembly as it is one of the most promising methods for producing large, ordered structures from nanoscale objects.

The thesis has three main parts; assembly of cellulose nanofibrils (CNFs) and fundamentals associated with the processing technique, the combination of CNFs with silk fusion proteins and finally the assembly of amyloid-like protein nanofibrils (PNFs). In the CNFs assembly part, we have pursued the challenge of transferring the full potential of CNFs to macroscale materials. CNFs are the most abundant structural elements in biological systems and have impressively high strength and stiffness, yet natural or man-made cellulose composites are much weaker than the CNFs. We fabricated nanocellulose fibers in pursuit of maximal mechanical performance by hydrodynamically controlling the structural ordering of nanofibrils, resulting in continuous fibers with mechanical properties higher than any natural or man-made macroscale biopolymeric material (Young’s modulus 86 GPa and a tensile strength 1.57 GPa). As the hydrodynamic assembly process is largely dependent on fundamental phenomenon controlling rotational and translational diffusion, we have applied a novel methodology based on birefringence allowing time-resolved in-situ investigations of diffusion and network dynamics of nanofibrils including effects of anisotropic orientation distributions.

Genetic engineering enables the synthesis of bioengineered silk fusion proteins that can serve as a foundation of new biomaterials. However, silk proteins are difficult to process and cannot be obtained in large quantities from spiders. By combining CNFs with recombinant spider silk proteins (RSPs) we have fabricated strong, tough and bioactive nanocomposites.   We demonstrate how small amounts of silk fusion proteins added to CNFs give advanced bio-functionalities unattainable to wood-based CNFs alone. Finally, flow-assisted assembly is applied to fabricate a material from 100% non-crystalline protein building blocks with whey protein, a mixture with β-lactoglobulin as the main component, which self-assemble into amyloid-like PNFs stabilized by hydrogen bonds. We show how conditions during the fibrillation process affect properties and morphology of the PNFs. Furthermore, we compare the assembly of whey PNFs of distinct morphologies and show that PNFs can be assembled into strong microfibers without the addition of plasticizers or crosslinkers.

• 14.
Univ Hong Kong, Dept Mech Engn, Hong Kong, Hong Kong, Peoples R China.
Perturbation-indUniv Hong Kong, Dept Mech Engn, Hong Kong, Hong Kong, Peoples R Chinauced droplets for manipulating droplet structure and configuration in microfluidics2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, article id 084009Article in journal (Refereed)

In this work, we mechanically perturb a liquid-in-liquid jet to manipulate the size and structure of the droplets formed from break-up of the jet. The induced break-up is relatively insensitive to fluctuations in the surrounding fluid flow. When the amplitude of perturbations is large and the interfacial tension of the liquid-liquid system is low, the size of the droplets can be precisely tuned by controlling the rate at which the liquid exits the tip of the dispensing nozzle through the frequency of perturbation. When applied to microfluidic devices with the appropriate geometry, our perturbation-induced droplet approach offers a strategy to manipulating droplet structures. We demonstrate that by varying the imposed perturbation frequency and phase lag, the structure of the multi-compartmental drops and the configuration of the resultant drops in the same flow condition can be manipulated. Moreover, after careful treatment of the wettability of the devices, we show that the structure of the droplets can be precisely controlled to change from single emulsion to double emulsion within the same device. The perturbation-induced droplet generation represents a new paradigm in the engineering of droplets, enhancing current droplet-based technologies for applications ranging from particle fabrication to confined micro-reactions.

• 15.
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH Royal Institute of Technology.
Water-Induced Structural Rearrangements on the Nanoscale in Ultrathin Nanocellulose Films2019In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835Article in journal (Refereed)
• 16.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. RISE Bioeconomy, P.O. Box 5604, Stockholm, SwedenRISE Bioeconomy, P.O. Box 5604, Stockholm, Sweden. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 7, p. 6378-6388Article in journal (Refereed)

Nanoscale building blocks of many materials exhibit extraordinary mechanical properties due to their defect-free molecular structure. Translation of these high mechanical properties to macroscopic materials represents a difficult materials engineering challenge due to the necessity to organize these building blocks into multiscale patterns and mitigate defects emerging at larger scales. Cellulose nanofibrils (CNFs), the most abundant structural element in living systems, has impressively high strength and stiffness, but natural or artificial cellulose composites are 3-15 times weaker than the CNFs. Here, we report the flow-assisted organization of CNFs into macroscale fibers with nearly perfect unidirectional alignment. Efficient stress transfer from macroscale to individual CNF due to cross-linking and high degree of order enables their Young's modulus to reach up to 86 GPa and a tensile strength of 1.57 GPa, exceeding the mechanical properties of known natural or synthetic biopolymeric materials. The specific strength of our CNF fibers engineered at multiscale also exceeds that of metals, alloys, and glass fibers, enhancing the potential of sustainable lightweight high-performance materials with multiscale self-organization.

• 17.
Vellore Institute of Technology, India..
Study of performance and emission characteristics of a partially coated LHR SI engine blended with n-butanol and gasoline2013In: Alexandria Engineering Journal, ISSN 1110-0168, Vol. 52, no 3, p. 285-293Article in journal (Refereed)

To meet the present requirements of the automotive industry, there is continuous search to improve the performance, exhaust emission, and life of the IC engines. The meet the first two challenges, researchers are working both on newer engine technologies and fuels. Some of the published work indicates that coating on the combustion surface of the engine with ceramic material results in improved performance and reduced emission levels when fueled with alternate fuel blended fuels, and this serves as a base for this work. Normal-Butanol has molecular structure that is adaptable to gasoline, and it is considered as one of the alternative fuels for SI engines. Blending butanol with gasoline changes the properties of the fuel and alters the engine performance and emission characteristics. This is because heat which is released at a rate as a result of combustion of the compressed air–fuel mixture in the combustion chamber gets changed with respect to change fuel properties, air fuel ratio, and engine speed. An experimental investigation is carried out on a partially insulated single cylinder SI engine to study the performance and emission characteristics when fueled with two different blends of butanol and gasoline. The cylinder head surface and valves are coated with a ceramic material consisting of Zirconium dioxide (ZrO2) with 8% by weight of Yttrium Oxide (Y2O3) to a thickness of 0.3 mm by plasma spray method. Two different fuel blends containing 10% and 15% by volume of butanol in Gasoline are tested on an engine dynamometer using the uncoated and ceramic coated engines. The results strongly indicate that combination of ceramic coated engine and butanol gasoline blended fuel has potential to improve the engine performance.

• 18.
Indian Institute of Technology, India.
Exceptionally robust and conductive superhydrophobic free-standing films of mesoporous carbon nanocapsule/polymer composite for multifunctional applications2015In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 93, no 8, p. 492-501Article in journal (Refereed)

A novel mesoporous carbon nanocapsule (MCC)/polyvinylidene fluoride (PVDF) polymer composite based free-standing film with multifunctional properties is fabricated by a facile solution approach that is appropriate for dip coating, brush-on and spray applications. The MCC/PVDF composite film exhibits superhydrophobic properties with a water contact angle of approximately 160° and a sliding angle of 5°. The films have a high thermal stability (up to 350 °C in oxidative atmosphere) and are also electrically conductive (tunable from ∼10−3 S m−1 to 10−2 S m−1). The superhydrophobicity is retained even in highly corrosive acidic and basic conditions (pH 1.29–13.54, concentrated HNO3 exposure and ammonium hydroxide solution), as well in a wide humidity range (35–83%). The mesoporous carbon containers (∼100 nm–1 μm size) also provide an interesting platform for encapsulating a variety of functional nanomaterials and activate release, thereby adding to the multi-functionality of the superhydrophobic conductive films of exceptional environmental stability, mechanical strength (∼0.1 GPa) and flexibility.

• 19.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Biotechnology (BIO), Protein Technology. 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. Innventia AB, Sweden. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Biotechnology (BIO), Protein Technology. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
Ultrastrong and Bioactive Nanostructured Bio-Based Composites2017In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 5, p. 5148-5159Article in journal (Refereed)

Nature’s design of functional materials relies on smart combinations of simple components to achieve desired properties. Silk and cellulose are two clever examples from nature–spider silk being tough due to high extensibility, whereas cellulose possesses unparalleled strength and stiffness among natural materials. Unfortunately, silk proteins cannot be obtained in large quantities from spiders, and recombinant production processes are so far rather expensive. We have therefore combined small amounts of functionalized recombinant spider silk proteins with the most abundant structural component on Earth (cellulose nanofibrils (CNFs)) to fabricate isotropic as well as anisotropic hierarchical structures. Our approach for the fabrication of bio-based anisotropic fibers results in previously unreached but highly desirable mechanical performance with a stiffness of ∼55 GPa, strength at break of ∼1015 MPa, and toughness of ∼55 MJ m–3. We also show that addition of small amounts of silk fusion proteins to CNF results in materials with advanced biofunctionalities, which cannot be anticipated for the wood-based CNF alone. These findings suggest that bio-based materials provide abundant opportunities to design composites with high strength and functionalities and bring down our dependence on fossil-based resources.

• 20.
KTH, School of Engineering Sciences (SCI), Mechanics.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Mechanics.
Effect of cellulose nanofibril morphology on the strength and stiffness of macroscopic filaments2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal (Other academic)
• 21.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
Flow-assisted organization of nanostructured bio-based materials2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
• 22.
Vellore Institute of Technology, India.
Numerical simulation of mixed convection in a porous medium filled with water/Al2 O3 nanofluid2013In: Heat Transfer-Asian Research, ISSN 1099-2871, E-ISSN 1523-1496, Vol. 42, no 1, p. 46-59Article in journal (Refereed)

The present work encloses the application of a Brinkman-extended Darcy model in a problem concerning mixed convection ina lid-driven porous cavity using nanofluids. The transport equations are solved numerically by the finite volume method on a co-located grid arrangement using the Quadratic Upstream Interpolation for Convective Kinematics (QUICK) scheme. The effects of governing parameters, namely, Grashof number (Gr), Darcy number (Da), and solid volume fraction $(\chi)$, on the streamlines and the isotherms are studied. The present results are validated by favorable comparisons with previously published results and are in good agreement with them. The present numerical results show that the addition of nanoparticles to a base fluid has produced an augmentation of the heat transfer coefficient and it is found to increase significantly with an increase of the particle volume concentration. It is observed from the results that at the higher value of the Grashof number (Gr = 104), the average Nusselt number increases with an increase in the Darcy number for a constant solid volume fraction. The detailed results are reported by means of streamlines, isotherms, and Nusselt numbers

• 23.
VIT University, India.
Numerical Simulation of Mixed-Convection Flow in a Lid-Driven Porous Cavity Using Different Nanofluids2014In: Heat Transfer-Asian Research, ISSN 1099-2871, E-ISSN 1523-1496, Vol. 43, no 1, p. 1-16Article in journal (Refereed)

In this study, the effect of mixed convection flow in a lid-driven porous cavity using different nanoparticles, such as aluminum oxide (Al 2 O 3), copper (Cu), silver (Ag), and titanium dioxide (TiO 2), are investigated. The base fluid is considered as water. The transport equations are solved numerically by finite volume method on a co-located grid arrangement using quadratic upwind interpolation for convective kinematics (QUICK) scheme. A two-dimensional square cavity is considered for the present investigation whose horizontal walls are insulated. The cold left wall is moving up and hot right wall is moving down with equal velocities. The variations of temperature distribution, stream function, and Nusselt number (Nu) are analyzed at constant Grashof numbers (Gr), Richardson numbers (Ri), and Darcy numbers (Da) as 1 × 10 4, 100, and 0.1, respectively, for different nanoparticles. The present results are validated by favorable comparison with previously published literature. The predicted results clearly indicate that the presence of nanoparticles inside the porous media enhances the heat transfer significantly. It is observed from the numerical results that the average Nusselt numbers (Nu) were found to increase linearly with an increase in volume fraction (χ). For the given volume fraction, the average Nu is maximum for a silver-based nanoparticle.

• 24.
KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics.
Measuring rotary diffusion of dispersed cellulose nanofibrils using Polarized Optical MicroscopyManuscript (preprint) (Other academic)
• 25.
KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
On the applicability of time-resolved synchrotron X-ray techniques for studying rotary diffusion of dispersed cellulose nanofibrilsManuscript (preprint) (Other academic)
• 26.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
KTH, School of Biotechnology (BIO), Centres, Centre for Bioprocess Technology, CBioPT. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Spiber AB, Stockholm, Sweden.. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. RISE Bioecon, Stockholm, Sweden.. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
Bioactive composites of cellulose nanofibrils and recombinant silk proteins2019In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal (Other academic)
1 - 26 of 26
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