writer：Xing Gao a,1, Zhijun Shi b,1, Andrew Laua, Changqin Liu a, Guang Yang b, Vadim V. Silberschmidt a,?
keywords：Strain-rate softening， Deformation mechanisms， Microstructural changes In-aqua testing， Bacterial cellulose hydrogel
source：期刊
specific source：Materials Science and Engineering C
Issue time：2016年

This study is focused on anomalous strain-rate-dependent behaviour of bacterial cellulose (BC) hydrogel that can be strain-rate insensitive, hardening, softening, or strain-rate insensitive in various ranges of strain rate. BC hydrogel consists of randomly distributed nanofibres and a large content of freewater; thanks to its ideal biocompatibility, it is suitable for biomedical applications.Motivated by its potential applications in complex loading conditions of body environment, its time-dependent behaviourwas studied by means of in-aqua uniaxial tension tests at constanttemperature of 37 °C at various strain rates ranging from 0.0001 s?1 to 0.3 s?1. Experimental results reflect anomalous strain-rate-dependent behaviour that was not documented before. Micro-morphological observations allowed identification of deformation mechanisms at low and high strain rates in relation to microstructural changes. Unlike strain-rate softening behaviours in other materials, reorientation of nanofibres and kinematics of free-water flow dominate the softening behaviour of BC hydrogel at high strain rates.