Anisotropic Hydrogel from Complexation-Driven Reorientation of Semirigid Polyanion at Ca2+ Diffusion Flux Front

作者：Wu Zi Liang; Kurokawa Takayuki; Sawada Daisuke; Hu Jian; Furukawa Hidemitsu; Gong Jian Ping^*

来源：Macromolecules, 2011, 44(9): 3535-3541.

DOI：10.1021/ma2001228

We report a macroscopically anisotropic hydrogel developed by the facile dialysis of a synthetic semirigid polyanion in aqueous solution of multivalent cations. By the uniaxial diffusion of Ca2+ into two ends of a thin rectangular reaction cell containing semirigid polyanion poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT) aqueous solution, centimeter-scale anisotropic hydrogels with the PBDT molecules and their self-assembled fibrous bundles align in perpendicular to the Ca2+ diffusion direction are obtained. The anisotropic gel shows a higher elastic modulus and tensile fracture stress/strain in the direction parallel to the PBDT orientation than that of perpendicular direction. By observing in situ the gelation process, an extraordinary molecular reorientation of PBDT at the Ca2+ diffusion flux front is observed for the first time. The mechanism for the molecular reorientation is discussed in terms of complexation and gelation.

• 出版日期2011-5-10