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Lindh, Erik L.
Publications (4 of 4) Show all publications
Lindh, E. L., Terenzi, C., Salmén, L. & Furo, I. (2017). Water in cellulose: evidence and identification of immobile and mobile adsorbed phases by H-2 MAS NMR. Physical Chemistry, Chemical Physics - PCCP, 19(6), 4360-4369
Open this publication in new window or tab >>Water in cellulose: evidence and identification of immobile and mobile adsorbed phases by H-2 MAS NMR
2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 6, p. 4360-4369Article in journal (Refereed) Published
Abstract [en]

The organization of water molecules adsorbed onto cellulose and the supramolecular hydrated structure of microfibril aggregates represents, still today, one of the open and complex questions in the physical chemistry of natural polymers. Here, we investigate by H-2 MAS NMR the mobility of water molecules in carefully H-2-exchanged, and thereafter re-dried, microcrystalline cellulose. By subtracting the spectral contribution of deuteroxyls from the spectrum of hydrated cellulose, we demonstrate the existence of two distinct (H2O)-H-2 spectral populations associated with mobile and immobile water environments, between which the water molecules do not exchange at the NMR observation time scale. We conclude that those two water phases are located at differently-accessible adsorption sites, here assigned to the cellulose surfaces between and within the microfibril aggregates, respectively. The superior performance of H-2 MAS NMR encourages further applications of the same method to other complex systems that expose heterogeneous hygroscopic surfaces, like wood cell walls.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-205076 (URN)10.1039/c6cp08219j (DOI)000395526600020 ()28119980 (PubMedID)2-s2.0-85027254163 (Scopus ID)
Note

QC 20170626

Available from: 2017-06-26 Created: 2017-06-26 Last updated: 2017-10-20Bibliographically approved
Lindh, E. L., Bergenstråhle-Wohlert, M., Terenzi, C., Salmén, L. & Furó, I. (2016). Non-exchanging hydroxyl groups on the surface of cellulose fibrils: The role of interaction with water. Carbohydrate Research, 434, 136-142
Open this publication in new window or tab >>Non-exchanging hydroxyl groups on the surface of cellulose fibrils: The role of interaction with water
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2016 (English)In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 434, p. 136-142Article in journal (Refereed) Published
Abstract [en]

The interaction of water with cellulose stages many unresolved questions. Here 2H MAS NMR and IR spectra recorded under carefully selected conditions in 1H-2H exchanged, and re-exchanged, cellulose samples are presented. It is shown here, by a quantitative and robust approach, that only two of the three available hydroxyl groups on the surface of cellulose fibrils are exchanging their hydrogen with the surrounding water molecules. This finding is additionally verified and explained by MD simulations which demonstrate that the 1HO(2) and 1HO(6) hydroxyl groups of the constituting glucose units act as hydrogen-bond donors to water, while the 1HO(3) groups behave exclusively as hydrogen-bond acceptors from water and donate hydrogen to their intra-chain neighbors O(5). We conclude that such a behavior makes the latter hydroxyl group unreactive to hydrogen exchange with water.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
2H MAS NMR, Cellulose, Deuterium exchange, FT-IR, Hydroxyl groups, Molecular-dynamics simulation
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-195208 (URN)10.1016/j.carres.2016.09.006 (DOI)000386861400018 ()27662030 (PubMedID)2-s2.0-84988316977 (Scopus ID)
Funder
Swedish Foundation for Strategic Research , ICA10-0086Swedish Research Council, VR 2012-03244
Note

QC 20161206

Available from: 2016-12-06 Created: 2016-11-02 Last updated: 2020-03-09Bibliographically approved
Lindh, E. L. & Salmén, L. (2016). Surface accessibility of cellulose fibrils studied by hydrogen-deuterium exchange with water. Cellulose (London), 24(1), 21-33
Open this publication in new window or tab >>Surface accessibility of cellulose fibrils studied by hydrogen-deuterium exchange with water
2016 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 1, p. 21-33Article in journal (Refereed) Published
Abstract [en]

A problem with cellulose-based materials is that they are highly influenced by moisture, leading to reduced strength properties with increasing moisture content. By achieving a more detailed understanding of the water–cellulose interactions, the usage of cellulose-based materials could be better optimized. Two different exchange processes of cellulose hydroxyl/deuteroxyl groups have been monitored by transmission FT-IR spectroscopy. By using line-shape-assisted deconvolution of the changing intensities, we have been able to follow the exchange kinetics in a very detailed and controlled manner. The findings reveal a hydrogen exchange that mainly is located at two different kinds of fibril surfaces, where the differences arise from the water accessibility of that specific surface. The slowly accessible regions are proposed to be located between the fibrils inside of the aggregates, and the readily accessible regions are suggested to be at the surfaces of the fibril aggregates. It was also possible to identify the ratio of slowly and readily accessible surfaces, which indicated that the average aggregate of cotton cellulose is built up by approximately three fibrils with an assumed average size of 12 × 12 cellulose chains. Additionally, the experimental setup enabled visualizing and discussing the implications of some of the deviating spectral features that are pronounced when recording FT-IR spectra of deuterium-exchanging cellulose: the insufficient red shift of the stretching vibrations and the vastly decreasing line widths.

Place, publisher, year, edition, pages
Springer, 2016
Keywords
Cellulose, Deuterium, FT-IR, Hydrogen bond, Exchange, Morphology
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-199199 (URN)10.1007/s10570-016-1122-8 (DOI)000392070700003 ()2-s2.0-84995741409 (Scopus ID)
Note

QC 20161230

Available from: 2016-12-29 Created: 2016-12-29 Last updated: 2017-11-29Bibliographically approved
Lindh, E. L., Terenzi, C., Furo, I. & Salmén, L. (2015). Identifying different hydroxyl populations in cellulose by 2H MAS NMR. Abstract of Papers of the American Chemical Society, 249
Open this publication in new window or tab >>Identifying different hydroxyl populations in cellulose by 2H MAS NMR
2015 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2015
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-243690 (URN)000411183301762 ()
Note

QC 20190305

Available from: 2019-03-05 Created: 2019-03-05 Last updated: 2019-03-05Bibliographically approved
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