Perspectives in the modeling of biopolymer aerogel networks subject to wetting

Abstract

Alginate-based aerogels were shown to be non-cytotoxic and to feature good cell adhesion, thus drawing their attention towards tissue engineering and regenerative medicine [1]. To this end, their mechanical properties under dry as well as wet conditions were subsequently investigated [2]. Upon wetting, these aerogels showed strong stiffening in their mechanical behavior. In this work, a micromechanically motivated model approach to describe this phenomenon is proposed. The nanofibers in the aerogel network are considered to undergo structural rearrangement upon being subjected to water. Furthermore, the collapse of the micropores (pore diameter below 5 nm) results in the formation of local hydrogel-like network phase. The constitutive model is based upon the assumption that the total network can be decomposed into a hydrogel-like network and a restructured aerogel network. The aerogel network is described based on the micromechanical model proposed by Rege et al. [3], while the hydrogel-like network is modeled based on the phenomenological approach of Gent [4]. This first approach towards modeling shows reliable results against the experimental stress-strain curves of alginate-starch aerogels [5].