Facile, Energy Efficient Microscale Fibrillation of Polyacrylamides under Ambient Conditions.

Abstract

Insight into fibre formation can provide new rationale for the design and preparation of fibres with programmed mechanical properties. While synthetic bioinspired fibres have shown impressive tensile properties, the fibre formation process remains poorly understood. Moreover, these systems are highly complex and their formation is environmentally and economically costly. We demonstrate controlled fibre formation under ambient conditions from polyacrylamide solutions with properties comparable to natural fibres such as wool and coir. Photopolymerization and subsequent microscale fibrillation of different acrylamides in water/ethanol mixtures a simple yields an energy-efficient route to fibre formation. This strategy reduces required processing energy by two-to-three orders of magnitude. Through extensive experimental elucidation, insight into precise fibre forming conditions of polymeric solutions was achieved. Ethanol was utilized as a chain transfer agent to control molecular weight of the polyacrylamides and the entanglement regimes of the solutions were determined through rheological characterization showing fibre formation above the entanglement concentration. Unique from previously reported hydrogel microfibres, we have shown that we can obtain fibres with good mechanical properties without the need for composites or crosslinkers. The reported approach offers a platform for fibre formation under ambient conditions with molecular level understanding of their assembly. This article is protected by copyright. All rights reserved.