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Rheology of cellulose nanofibrils in the presence of surfactants

Title
Rheology of cellulose nanofibrils in the presence of surfactants
Author
김진웅
Keywords
NONIONIC SURFACTANTS; AQUEOUS SUSPENSIONS; COLLOIDAL GLASS; GELS; HOMOGENIZATION; NETWORKS; SHEAR; ADSORPTION; DYNAMICS; LAPONITE
Issue Date
2016-01
Publisher
ROYAL SOC CHEMISTRY
Citation
SOFT MATTER, v. 12, NO 1, Page. 157-164
Abstract
Cellulose nanofibrils (CNFs) present unique opportunities for rheology modification in complex fluids. Here we systematically consider the effect of ionic and non-ionic surfactants on the rheology of dilute CNF suspensions. Neat suspensions are transparent yield-stress fluids which display strong shear thinning and power-law dependence of modulus on concentration, G' similar to c(2.1). Surfactant addition below a critical mass concentration cc produces an increase in the gel modulus with retention of optical clarity. Larger than critical concentrations induce significant fibril aggregation leading to the loss of suspension stability and optical clarity, and to aggregate sedimentation. The critical concentration was the lowest for a cationic surfactant (DTAB), c(c) approximate to 0.08%, while suspension stability was retained for non-ionic surfactants (Pluronic F68, TX100) at concentrations up to 8%. The anionic surfactant SDS led to a loss of stability at c(c) approximate to 1.6% whereas suspension stability was not compromised by anionic SLES up to 8%. Dynamic light scattering data are consistent with a scenario in which gel formation is driven by micelle-nanofibril bridging mediated by associative interactions of ethoxylated surfactant headgroups with the cellulose fibrils. This may explain the strong difference between the properties of SDS and SLES-modified suspensions. These results have implications for the use of CNFs as a rheology modifier in surfactant-containing systems.
URI
http://pubs.rsc.org/en/Content/ArticleLanding/2016/SM/C5SM01803J#!divAbstracthttp://hdl.handle.net/20.500.11754/30601
ISSN
1744-683X; 1744-6848
DOI
10.1039/c5sm01803j
Appears in Collections:
GRADUATE SCHOOL[S](대학원) > BIONANOTECHNOLOGY(바이오나노학과) > Articles
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