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Wärnheim, A., Saarimaa, V., Heydari, G., Sundell, P.-E., Deltin, T., Johnson, C. M., . . . Persson, D. (2025). Multiscale Analysis of pigment effects on weathering of Polyester Coatings: From Nanoscale Chemistry to Macroscale Performance. npj Materials Degradation, 9(66)
Open this publication in new window or tab >>Multiscale Analysis of pigment effects on weathering of Polyester Coatings: From Nanoscale Chemistry to Macroscale Performance
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2025 (English)In: npj Materials Degradation, E-ISSN 2397-2106, Vol. 9, no 66Article in journal (Refereed) Published
Abstract [en]

Almost all organic coatings used for corrosion protection contain various types of pigmentation, both for the sake of aesthetics and performance. By focusing on spatially resolved vibrational spectroscopy and electron microscopy, we demonstrate that the type of pigmentation has a fundamental effect on both localized and global degradation processes across the investigated coatings. Samples with white TiO2 pigments display low macroscale chemical degradation across the surface but do experience a significant change in topography. SEM-EDS imaging shows that µm-scale craters are formed around the TiO2 pigments. Nanoscale spatially resolved IR spectroscopy (AFM-IR) suggests that this local erosion is not triggered by reactions seen in coatings with other types of pigments. However, FTIR-ATR chemical imaging of coating cross sections confirmed that the TiO2 pigments also protects material beneath the surface, resulting in very shallow chemical degradation effects as compared to the other systems. Darker coatings, containing carbon black, experience moderate to high chemical degradation across the surface, and additionally the degradation propagates deep into the coatings. Overall, this paper highlights that single criteria should not be used when comparing the degradation of different coatings.

Place, publisher, year, edition, pages
Springer Nature, 2025
National Category
Analytical Chemistry Polymer Chemistry Materials Engineering
Identifiers
urn:nbn:se:kth:diva-356717 (URN)10.1038/s41529-025-00617-3 (DOI)
Note

QC 20250609

Available from: 2024-11-20 Created: 2024-11-20 Last updated: 2025-06-09Bibliographically approved
Kotov, N., Keskitalo, M. M. & Johnson, C. M. (2025). Nano FTIR spectroscopy of liquid water in the –OH stretching region. Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, 330, Article ID 125640.
Open this publication in new window or tab >>Nano FTIR spectroscopy of liquid water in the –OH stretching region
2025 (English)In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 330, article id 125640Article in journal (Refereed) Published
Abstract [en]

Nano-FTIR spectroscopy is a technique where atomic force microscopy (AFM) and infrared (IR) spectroscopy are combined to obtain chemical information with a lateral resolution of some tens of nm. It has been used to study numerous solid surfaces and recently also liquids including water have been examined by separating the liquid from the AFM tip by a thin lid. However, although the water stretching vibrations are significantly more intense than the bending vibration in conventional IR spectroscopy, only the bending vibration has been observed in nano-FTIR spectroscopy so far. In this article we show that also the stretching vibrations of liquid H2O, D2O, HOD, and aqueous salt solutions can be probed in nano-FTIR spectroscopy. Nano-FTIR absorption and phase spectra have been acquired at different harmonics and it was found the third optical harmonic (O3) in the nano-FTIR absorption spectra exhibited the highest resemblance with attenuated total reflection (ATR). Being able to probe water stretching vibrations with nano-FTIR spectroscopy is of importance since the stretching vibrations contain considerably more detailed information regarding for example hydrogen bonding strength than the bending vibration. In addition, it enables studies of the essential interactions between water and biomolecules. Furthermore, this work highlights both advantages and challenges that nano-FTIR spectroscopy in a liquid sample cell has and importance of further studies that lead to a better understanding of the near-field signals in liquids.

Place, publisher, year, edition, pages
Elsevier BV, 2025
Keywords
Aqueous solutions, ATR FTIR, D2O, Liquid sample cell, Nano-FTIR spectroscopy, Water stretching vibrations
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-358406 (URN)10.1016/j.saa.2024.125640 (DOI)001420321000001 ()39742622 (PubMedID)2-s2.0-85214214906 (Scopus ID)
Note

QC 20250303

Available from: 2025-01-15 Created: 2025-01-15 Last updated: 2025-03-03Bibliographically approved
Campos Pacheco, J. E., Yalovenko, T., Riaz, A., Kotov, N., Davids, C., Persson, A., . . . Valetti, S. (2024). Inhalable porous particles as dual micro-nano carriers demonstrating efficient lung drug delivery for treatment of tuberculosis. Journal of Controlled Release, 369, 231-250
Open this publication in new window or tab >>Inhalable porous particles as dual micro-nano carriers demonstrating efficient lung drug delivery for treatment of tuberculosis
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2024 (English)In: Journal of Controlled Release, ISSN 0168-3659, E-ISSN 1873-4995, Vol. 369, p. 231-250Article in journal (Refereed) Published
Abstract [en]

Inhalation therapy treating severe infectious disease is among the more complex and emerging topics in controlled drug release. Micron-sized carriers are needed to deposit drugs into the lower airways, while nano-sized carriers are of preference for cell targeting. Here, we present a novel and versatile strategy using micron-sized spherical particles with an excellent aerodynamic profile that dissolve in the lung fluid to ultimately generate nanoparticles enabling to enhance both extra- and intra-cellular drug delivery (i.e., dual micro-nano inhalation strategy). The spherical particles are synthesised through the condensation of nano-sized amorphous silicon dioxide resulting in high surface area, disordered mesoporous silica particles (MSPs) with monodispersed size of 2.43 μm. Clofazimine (CLZ), a drug shown to be effective against multidrug-resistant tuberculosis, was encapsulated in the MSPs obtaining a dry powder formulation with high respirable fraction (F.P.F. <5 μm of 50%) without the need of additional excipients. DSC, XRPD, and Nitrogen adsorption-desorption indicate that the drug was fully amorphous when confined in the nano-sized pores (9–10 nm) of the MSPs (shelf-life of 20 months at 4 °C). Once deposited in the lung, the CLZ-MSPs exhibited a dual action. Firstly, the nanoconfinement within the MSPs enabled a drastic dissolution enhancement of CLZ in simulated lung fluid (i.e., 16-fold higher than the free drug), increasing mycobacterial killing than CLZ alone (p = 0.0262) and reaching concentrations above the minimum bactericidal concentration (MBC) against biofilms of M. tuberculosis (i.e., targeting extracellular bacteria). The released CLZ permeated but was highly retained in a Calu-3 respiratory epithelium model, suggesting a high local drug concentration within the lung tissue minimizing risk for systemic side effects. Secondly, the micron-sized drug carriers spontaneously dissolve in simulated lung fluid into nano-sized drug carriers (shown by Nano-FTIR), delivering high CLZ cargo inside macrophages and drastically decreasing the mycobacterial burden inside macrophages (i.e., targeting intracellular bacteria). Safety studies showed neither measurable toxicity on macrophages nor Calu-3 cells, nor impaired epithelial integrity. The dissolved MSPs also did not show haemolytic effect on human erythrocytes. In a nutshell, this study presents a low-cost, stable and non-invasive dried powder formulation based on a dual micro-nano carrier to efficiently deliver drug to the lungs overcoming technological and practical challenges for global healthcare.

Place, publisher, year, edition, pages
Elsevier B.V., 2024
Keywords
Clofazimine, Disordered mesoporous silica particles, Dissolution enhancement, Dried powder formulation, Dual micro-nano carrier, Lung drug delivery, Soluble carrier
National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:kth:diva-345239 (URN)10.1016/j.jconrel.2024.03.013 (DOI)001219489000001 ()38479444 (PubMedID)2-s2.0-85189001903 (Scopus ID)
Note

QC 20240524

Available from: 2024-04-10 Created: 2024-04-10 Last updated: 2024-08-28Bibliographically approved
Kral, M., Dendisova, M., Svoboda, J., Cernescu, A., Svecova, M., Johnson, C. M., . . . Matejka, P. (2024). Nano-FTIR spectroscopy of surface confluent polydopamine films – What is the role of deposition time and substrate material?. Colloids and Surfaces B: Biointerfaces, 235, Article ID 113769.
Open this publication in new window or tab >>Nano-FTIR spectroscopy of surface confluent polydopamine films – What is the role of deposition time and substrate material?
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2024 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 235, article id 113769Article in journal (Refereed) Published
Abstract [en]

Polydopamine (PDA) is a widely used anchoring layer for multiple purposes. While simple to prepare, PDA is characterized by high chemical and topological diversity, which can limit its versatility. Unraveling the formation mechanism and physicochemical properties of continuous confluent layer and adherent nanoparticles on the nanoscale is crucial to further extend the prospective applications of PDA. Utilizing nano-FTIR spectroscopy, we investigate layers of PDA on three different substrates (silicon/silicon dioxide, nitrogen-doped titanium oxide, and gold substrates) at varying times of deposition (ToD). We observed a good correlation between the nano-FTIR and macroscopic FTIR spectra that reflected the changes in the relative abundance of PDA and polymerization intermediates as ToD increased. To gain analytical power, we utilized the principal component analysis (PCA) and extracted additional information from the resulting loadings spectral curves and data distribution in the score plots. We revealed a higher variability of the spectra of ultrathin surface confluent layers compared to the adherent nanoparticles. While the spectra of nanoparticles showed no apparent dependency on either ToD or the substrate material, the spectra of layers were highly affected by the increasing ToD and exhibited a rise in the absorption of PDA. Concomitantly, the spectra of layers grouped according to the substrate material at the lowest ToD point to the fact that the substrate material affects the PDA's initial physicochemical structure. The observed separation gradually diminished with the increasing ToD as the PDA physicochemical structure became less influenced by the substrate material.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Anchoring layers, Infrared, Nano-FTIR, Polydopamine, Self-assembly, Vibrational nanoscopy
National Category
Materials Chemistry Surface- and Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-343476 (URN)10.1016/j.colsurfb.2024.113769 (DOI)001176544500001 ()38306803 (PubMedID)2-s2.0-85184044379 (Scopus ID)
Note

QC 20240215

Available from: 2024-02-15 Created: 2024-02-15 Last updated: 2025-02-09Bibliographically approved
Wärnheim, A., Kotov, N., Dobryden, I., Telaretti Leggieri, R., Edvinsson, C., Heydari, G., . . . Claesson, P. M. (2024). Nanomechanical and nano-FTIR analysis of polyester coil coatings before and after artificial weathering experiments. Progress in organic coatings, 190, Article ID 108355.
Open this publication in new window or tab >>Nanomechanical and nano-FTIR analysis of polyester coil coatings before and after artificial weathering experiments
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2024 (English)In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 190, article id 108355Article in journal (Refereed) Published
Abstract [en]

Local heterogeneities can have significant effects on the performance of anti-corrosion coatings. Even small features can act as initiation points for damage and result in corrosion of the substrate material. Analysis methods with high spatial resolution and the ability to collect information relevant to crosslinking and degradation behavior of these coatings are therefore highly relevant. In this work, we demonstrate the utility of nanomechanical AFM measurements and nano-FTIR in investigating the nanoscale mechanical and chemical properties of two polyester coil coating clearcoats before and after weathering. On the nanoscale, weathering led to a stiffer and less deformable coating with less variation in the nanomechanical properties. Chemical degradation was quantified using changes in band ratios in the IR-spectra. Macro and nano-scale measurements showed similar trends with the latter measurements showing larger heterogeneity. Our results demonstrate the usefulness of the described analysis techniques and will pave the way for future studies of local properties in other coating systems and formulations.

Place, publisher, year, edition, pages
Elsevier BV, 2024
National Category
Materials Engineering
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-326839 (URN)10.1016/j.porgcoat.2024.108355 (DOI)001223181600001 ()2-s2.0-85188822290 (Scopus ID)
Funder
Swedish Foundation for Strategic Research, FID18-0034
Note

QC 20230522

Available from: 2023-05-12 Created: 2023-05-12 Last updated: 2024-11-24Bibliographically approved
Kotov, N., Larsson, P. A., Jain, K., Abitbol, T., Cernescu, A., Wågberg, L. & Johnson, C. M. (2023). Elucidating the fine-scale structural morphology of nanocellulose by nano infrared spectroscopy. Carbohydrate Polymers, 302, Article ID 120320.
Open this publication in new window or tab >>Elucidating the fine-scale structural morphology of nanocellulose by nano infrared spectroscopy
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2023 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 302, article id 120320Article in journal (Refereed) Published
Abstract [en]

Nanoscale infrared (IR) spectroscopy and microscopy, enabling the acquisition of IR spectra and images with a lateral resolution of 20 nm, is employed to chemically characterize individual cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) to elucidate if the CNCs and CNFs consist of alternating crystalline and amorphous domains along the CNF/CNC. The high lateral resolution enables studies of the nanoscale morphology at different domains of the CNFs/CNCs: flat segments, kinks, twisted areas, and end points. The types of nano-cellulose investigated are CNFs from tunicate, CNCs from cotton, and anionic and cationic wood-derived CNFs. All nano-FTIR spectra acquired from the different samples and different domains of the individual nanocellulose particles resemble a spectrum of crystalline cellulose, suggesting that the non-crystalline cellulose signal observed in macroscopic measurements of nanocellulose most likely originate from cellulose chains present at the surface of the nanocellulose particles.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Nanocellulose, Cellulose nanocrystals, Cellulose nanofibrils, Crystalline and amorphous domains, Nano-FTIR spectroscopy, S-SNOM
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-322846 (URN)10.1016/j.carbpol.2022.120320 (DOI)000891746700002 ()36604038 (PubMedID)2-s2.0-85142692194 (Scopus ID)
Note

QC 20230109

Available from: 2023-01-09 Created: 2023-01-09 Last updated: 2023-07-03Bibliographically approved
Abitbol, T., Kubat, M., Brännvall, E., Kotov, N., Johnson, C. M., Nizamov, R., . . . Guerreiro, M. P. (2023). Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps. ACS Omega, 8(24), 21474-21484
Open this publication in new window or tab >>Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps
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2023 (English)In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 24, p. 21474-21484Article in journal (Refereed) Published
Abstract [en]

From a circular economyperspective, one-pot strategies for theisolation of cellulose nanomaterials at a high yield and with multifunctionalproperties are attractive. Here, the effects of lignin content (bleachedvs unbleached softwood kraft pulp) and sulfuric acid concentrationon the properties of crystalline lignocellulose isolates and theirfilms are explored. Hydrolysis at 58 wt % sulfuric acid resulted inboth cellulose nanocrystals (CNCs) and microcrystalline celluloseat a relatively high yield (>55%), whereas hydrolysis at 64 wt% gaveCNCs at a lower yield (<20%). CNCs from 58 wt % hydrolysis weremore polydisperse and had a higher average aspect ratio (1.5-2x),a lower surface charge (2x), and a higher shear viscosity (100-1000x).Hydrolysis of unbleached pulp additionally yielded spherical nanoparticles(NPs) that were <50 nm in diameter and identified as lignin bynanoscale Fourier transform infrared spectroscopy and IR imaging.Chiral nematic self-organization was observed in films from CNCs isolatedat 64 wt % but not from the more heterogeneous CNC qualities producedat 58 wt %. All films degraded to some extent under simulated sunlighttrials, but these effects were less pronounced in lignin-NP-containingfilms, suggesting a protective feature, but the hemicellulose contentand CNC crystallinity may be implicated as well. Finally, heterogeneousCNC compositions obtained at a high yield and with improved resourceefficiency are suggested for specific nanocellulose uses, for instance,as thickeners or reinforcing fillers, representing a step toward thedevelopment of application-tailored CNC grades.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Surface- and Corrosion Engineering
Research subject
Chemical Engineering; Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-327836 (URN)10.1021/acsomega.3c00295 (DOI)001009808200001 ()37360452 (PubMedID)2-s2.0-85162876606 (Scopus ID)
Funder
Swedish Research Council Formas, 2019-02508Swedish Research Council Formas, 2019-02508
Note

QC 20231122

Available from: 2023-05-31 Created: 2023-05-31 Last updated: 2025-02-09Bibliographically approved
Zhao, W., Babu, P., Chang, T., Odnevall Wallinder, I., Hedström, P., Johnson, C. M. & Leygraf, C. (2022). Initial atmospheric corrosion studies of copper from macroscale to nanoscale in a simulated indoor atmospheric environment. Corrosion Science, 195, Article ID 109995.
Open this publication in new window or tab >>Initial atmospheric corrosion studies of copper from macroscale to nanoscale in a simulated indoor atmospheric environment
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2022 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 195, article id 109995Article in journal (Refereed) Published
Abstract [en]

Corrosion effects on copper exposed in a humid atmosphere with formic acid (mimicking indoor corrosion) have been explored through successive increase in surface lateral resolution from macroscale (IRRAS, GIXRD) over microscale (LOM, SEM, IR microscopy) to nanoscale (Nano-FTIR, FIB/SEM/EDS). Initial more uniform growth of Cu2O is followed by more varying topography and thickness until local removal of Cu2O enables the aqueous adlayer to react with the copper substrate. Local formation of Cu(OH)(HCOO) and adjacent Cu2O provide microscopic and spectroscopic evidence of corrosion cells. Nano-FTIR shows that the density of Cu(OH)(HCOO) nuclei, but not their size, increases with exposure time.

Place, publisher, year, edition, pages
Elsevier BV, 2022
Keywords
Copper, Atmospheric corrosion, Nano-FTIR, SEM, FIB, EDS, Corrosion cell
National Category
Surface- and Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-311883 (URN)10.1016/j.corsci.2021.109995 (DOI)000783072900002 ()2-s2.0-85120685093 (Scopus ID)
Note

QC 20220506

Available from: 2022-05-06 Created: 2022-05-06 Last updated: 2025-02-09Bibliographically approved
Xu, W., Mihhels, K., Kotov, N., Lepikko, S., Ras, R. H. A., Johnson, C. M., . . . Kontturi, E. (2022). Solid-state polymer adsorption for surface modification: The role of molecular weight. Journal of Colloid and Interface Science, 605, 441-450
Open this publication in new window or tab >>Solid-state polymer adsorption for surface modification: The role of molecular weight
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2022 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 605, p. 441-450Article in journal (Refereed) Published
Abstract [en]

Hypothesis: Solid-state polymer adsorption offers a distinct approach for surface modification. These ultrathin, so-called Guiselin layers can easily be obtained by placing a polymer melt in contact with an interface, followed by a removal of the non-adsorbed layer with a good solvent. While the mechanism of formation has been well established for Guiselin layers, their stability, crucial from the perspective of materials applications, is not. The stability is a trade-off in the entropic penalty between cooperative detachment of the number of segments directly adsorbed on the substrate and consecutively pinned monomers. Experiments: Experimental model systems of Guiselin layers of polystyrene (PS) on silicon wafers with native oxide layer on top were employed. The stability of the adsorbed layers was studied as a function of PS molecular weight and polydispersibility by various microscopic and spectroscopic tools as well as quasi-static contact angle measurements. Findings: Adsorbed layers from low molecular weight PS were disrupted with typical spinodal decomposition patterns whereas high molecular weight (>500 kDa) PS resulted in stable, continuous layers. Moreover, we show that Guiselin layers offer an enticing way to modify a surface, as demonstrated by adsorbed PS that imparts a hydrophobic character to initially hydrophilic silicon wafers.

Place, publisher, year, edition, pages
Elsevier BV, 2022
Keywords
Contact angle, Dewetting, Polymer adsorption, Polystyrene, Silicon wafers, Surface modification
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-303890 (URN)10.1016/j.jcis.2021.07.062 (DOI)000704404400008 ()34333417 (PubMedID)2-s2.0-85111278426 (Scopus ID)
Note

QC 20211027

Available from: 2021-10-27 Created: 2021-10-27 Last updated: 2023-07-03Bibliographically approved
Zhao, W., Chang, T., Leygraf, C. & Johnson, C. M. (2021). Corrosion inhibition of copper with octadecylphosphonic acid (ODPA) in a simulated indoor atmospheric environment. Corrosion Science, 192(109777)
Open this publication in new window or tab >>Corrosion inhibition of copper with octadecylphosphonic acid (ODPA) in a simulated indoor atmospheric environment
2021 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 192, no 109777Article in journal (Refereed) Published
Abstract [en]

The corrosion inhibition of self-assembled octadecylphosphonic acid (ODPA) layers on non-oxidized and pre-oxidized copper and Langmuir-Blodgett deposited ODPA layers on pre-oxidized copper was investigated under a simulated indoor atmospheric corrosion environment containing 80% RH and 100 ppb formic acid. The corrosion process was monitored in-situ with infrared absorption/reflection spectroscopy, and the corrosion products were further characterised by grazing incidence X-ray diffraction. Nano-FTIR microscopy was used to reveal the nature, size, and distribution of the corrosion products on the nanoscale. The combination of pre-formed cuprite and ODPA layers, both with only some nanometres thickness, provided an excellent protection under this environment.

Place, publisher, year, edition, pages
Elsevier BV, 2021
National Category
Surface- and Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-302660 (URN)10.1016/j.corsci.2021.109777 (DOI)000700924900002 ()2-s2.0-85113958426 (Scopus ID)
Note

QC 20211011

Available from: 2021-09-28 Created: 2021-09-28 Last updated: 2025-02-09Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8537-0881

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