Reversible Gelation of Rod-Like Viruses Grafted with Thermoresponsive Polymers

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• 作者：Zhenkun Zhang ; Naveen Krishna ; M. Paul Lettinga ; Jan Vermant ; Eric Grelet
• 刊名：Langmuir
• 出版年：2009
• 出版时间：February 17, 2009
• 年：2009
• 卷：25
• 期：4
• 页码：2437-2442
• 全文大小：315K
• 年卷期：v.25,no.4(February 17, 2009)
• ISSN：1520-5827

文摘

The synthesis and selected macroscopic properties of a new model system consisting of poly(N-isopropylacrylamide) (PNIPAM)-coated rod-like fd virus particles are presented. The sticky rod-like colloids can be used to study effect of particle shape on gelation transition, the structure and viscoelasticity of isotropic and nematic gels, and to make both open isotropic as well as ordered nematic particle networks. This model system of rod-like colloids, for which the strength of attraction between the particles is tunable, is obtained by chemically grafting highly monodisperse rod-like fd virus particles with thermoresponsive polymers, e.g. PNIPAM. At room temperature, suspensions of the resulting hybrid PNIPAM-fd are fluid sols which are in isotropic or liquid crystalline phases, depending on the particle concentration and ionic strength. During heating/cooling, the suspensions change reversibly between sol and gel state near a critical temperature of 32 °C, close to the lower critical solution temperature of free PNIPAM. The so-called nematic gel, which exhibits a cholesteric feature, can therefore be easily obtained. The gelation behavior of PNIPAM-fd system and the structure of the nematic gel have been characterized by rheology, optical microscopy and small-angle X-ray scattering.