Tuning Cellulose Nanocrystal Gelation with Polysaccharides and Surfactants

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• 作者：Zhen Hu ; Emily D. Cranston ; Robin Ng ; Robert Pelton
• 刊名：Langmuir
• 出版年：2014
• 出版时间：March 18, 2014
• 年：2014
• 卷：30
• 期：10
• 页码：2684-2692
• 全文大小：366K
• 年卷期：v.30,no.10(March 18, 2014)
• ISSN：1520-5827

文摘

Gelation of cellulose nanocrystal (CNC) dispersions was measured as a function of the presence of four nonionic polysaccharides. Addition of hydroxyethyl cellulose (HEC), hydroxypropyl guar (HPG), or locust bean gum (LBG) to CNC dispersions induced the gelation of dilute CNC dispersions, whereas dextran (DEX) did not. These behaviors correlated with adsorption tendencies; HEC, HPG, and LBG adsorbed onto CNC-coated quartz crystal microbalance sensors, whereas DEX did not adsorb. We propose that the adsorbing polysaccharides greatly increased the effective volume fraction of dilute CNC dispersions, driving more of the nanocrystals into anisotropic domains. SDS and Triton X-100 addition disrupted HEC鈥揅NC gels whereas CTAB did not. Surface plasmon resonance measurements with CNC-coated sensors showed that SDS and Triton X-100 partially removed adsorbed HEC, whereas CTAB did not. These behaviors illustrate the complexities associated with including CNC dispersions in formulated products: low CNC contents can induce spectacular changes in rheology; however, surfactants and soluble polymers may promote gel formation or induce CNC coagulation.