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 free water; 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 behaviour was studied by means of in-aqua uniaxial tension tests at constant temperature 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.
Funding
The authors would like to acknowledge the 7th European Community Framework Programme
for financial support through a Marie Curie International Research Staff Exchange Scheme
(IRSES) Project entitled “Micro-Multi-Material Manufacture to Enable Multifunctional Miniaturised Devices (M6)” (Grant No. PIRSES-GA-2010-269113). Additional support from China-European Union technology cooperation programme (Grant No. 1110) is also acknowledged.
History
School
Mechanical, Electrical and Manufacturing Engineering
Published in
Materials Science and Engineering C
Volume
62
Pages
130 - 136
Citation
GAO, X. ...et al., 2016. Effect of microstructure on anomalous strain-rate-dependent behaviour of bacterial cellulose hydrogel. Materials Science and Engineering C, 62, pp. 130-136.
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/
Publication date
2016
Notes
This paper was accepted for publication in the journal Materials Science and Engineering C and the definitive published version is available at http://dx.doi.org/10.1016/j.msec.2016.01.042.