Micelle Crosslinked Polyacrylic Acid Hydrogels with Resilience and Self-Recovery Properties

Abstract

Micelle crosslinking method is one of the several techniques to fabricate hydrogels with good mechanical performance. Micelle crosslinked hydrogels reported so far are fabricated using a multistep preparation process due to the functionalization of block copolymers or surfactants with acrylate, aldehyde, azo, or reversible addition-fragmentation chain transfer groups to create a polymer network. Herein, a simple one-step approach is introduced to produce resilient hydrogels prepared by bulk polymerization of acrylic acid and esterification with Triton X-100 (TX-100) in the presence of catalyst sulfuric acid (H2SO4). The advantage of this study is that TX-100 surfactants self-assembling into micelles are directly bonded onto polymer chains through an ester bond without any further modification. The obtained hydrogels exhibit tensile strengths up to 135 +/- 8 kPa and compressive strengths up to 16 +/- 1 MPa over 94% strains as well as complete self-recovery and high resilience abilities (approximate to 86% at strains up to 400%) originating from hydrophobic associations in the core of micelles acting as dynamic cross-linkers along with hydrogen bonds and entanglements between polymer chains acting as additional crosslink points. The overall results show that the hydrogels can be good candidate as elastic materials in many fields.