Weitere Artikel dieser Ausgabe durch Wischen aufrufen
The online version of this article (doi:10.1007/s10570-016-1080-1) contains supplementary material, which is available to authorized users.
Natural anisotropic building-blocks such as cellulose nanocrystals (CNCs) have attracted considerable attention due to their biodegradability and nanometer-size. In this work the colloidal behavior of CNCs, obtained from sulfuric acid hydrolysis of microcrystalline cellulose, has been studied in presence of salts of different valences. The influence on the colloidal stability and nature of aggregates has been investigated for monovalent salts (LiCl, NaCl, KCl, CsCl), divalent salts (CaCl2 and MgCl2), and a trivalent salt (AlCl3), both experimentally by means of turbidity and small angle X-ray scattering (SAXS) measurements, as well as by Monte Carlo simulations using a simple coarse-grained model. For the entire salt series, a critical aggregation concentration (CAC) could be determined by turbidity measurements, as a result of the reduction of effective Coulomb repulsions due to the presence of sulfate groups on the CNC surface. The CACs also followed the Schulze–Hardy law, i.e. the critical aggregation concentration decreased with increasing counterion valence. For the monovalent ions, the CACs followed the trend Li+ > Na+ > K+ > Cs+, which could be rationalized in terms of matching affinities between the cation and the sulfate groups present at the surface of CNCs. From the SAXS measurements it was shown that the density of the aggregates increased with increasing salt concentration and ion valence. In addition, these findings were rationalized by means of simulation, which showed a good correlation with experimental data. The combination of the experimental techniques and the simulations offered insight into interaction-aggregation relationship of CNC suspensions, which is of importance for their structural design applications.
Supplementary material 1 (PDF 2739 kb)10570_2016_1080_MOESM1_ESM.pdf
Berne BJ, Pecora R (2000) Dynamic light scattering: with applications to chemistry, biology, and physics. Dover Books on Physics, Dover edn. Dover Publications, Mineola
Borkovec M, Szilagyi I, Popa I, Finessi M, Sinha P, Maroni P, Papastavrou G (2012) Investigating forces between charged particles in the presence of oppositely charged polyelectrolytes with the multi-particle colloidal probe technique. Adv Colloid Interface Sci 179–182:85–98. doi: 10.1016/j.cis.2012.06.005CrossRef
Dufresne A (ed) (2012) Rheological behavior of nanocellulose suspensions and self-assembly. In: Nanocellulose: from nature to high performance tailored materials. Walter de Gruyter, Berlin
Håkansson KMO et al (2014) Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments. Nat Commun. doi: 10.1038/ncomms5018
Labrador A, Cerenius Y, Svensson C, Theodor K, Plivelic T (2013) The yellow mini-hutch for SAXS experiments at MAX IV laboratory. J Phys: Conf Ser 425:072019. doi: 10.1088/1742-6596/425/7/072019
Ninham BW, Lo Nostro P (2010) Molecular forces and self assembly in colloid, nano sciences and biology. Cambridge University Press, Cambridge CrossRef
Sano M, Kamino A, Shinkai S (2001) Construction of carbon nanotube “stars” with dendrimers. Angew Chem Int Edit 40:4661. doi: 10.1002/1521-3773(20011217)40:24<4661:Aid-Anie4661>3.0.Co;2-VCrossRef
- Aggregation behavior of aqueous cellulose nanocrystals: the effect of inorganic salts
- Springer Netherlands
Systemische Notwendigkeit zur Weiterentwicklung von Hybridnetzen