# Properties of Hydrogels Derived from Cationic Analogues of Bile Acid: Remarkably Distinct Flowing Characteristics

Sangeetha, Neralagatta M and Bhat, Shreedhar and Choudhury, Angshuman R and Maitra, Uday and Terech, Pierre (2004) Properties of Hydrogels Derived from Cationic Analogues of Bile Acid: Remarkably Distinct Flowing Characteristics. In: Journal of Physical Chemistry B, 108 (41). pp. 16056-16063.

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## Abstract

A new class of cationic bile acid derivatives was synthesized to gel water and aqueous electrolyte solutions. Investigations on these hydrogels are carried out at different length scales by a combination of physical techniques. Each of these hydrogels exhibits unique characteristics, thus providing a spectrum of thermal, optical, and mechanical properties. X-ray crystallographic investigation of the single crystals of two of the gelators shows significant differences in the solid-state packing. X-ray scattering experiments indicate that the gel state consists of a different morph than that in the solid. Electron microscopic investigations of the xerogels reveal the fibrous nature of the gel structure. These fibers are associated mainly through bundling processes. A detailed rheological study reveals significant differences in the mechanical properties of the three hydrogels. The storage modulus varies in the range $(0.2-2) \times 10^5$ Pa at C = 2 wt% for these systems. The exponents of the scaling of the rheological parameters with the concentration for two of the systems agree well with those expected for cellular solids or strongly interacting colloidal gels. A third system exhibits a singular behavior with the energy of interaction between the colloidal flocs increasing with the concentration.

Item Type: Journal Article The copyright for this article belongs to American Chemical Society. Division of Chemical Sciences > Organic Chemistry 20 Oct 2005 27 Aug 2008 11:30 http://eprints.iisc.ernet.in/id/eprint/3797