Deformation induced hydrophobicity: implications in spider silk formation

Abstract

A theoretical framework, which considers the effect of strong inter-polymer associations on phase separation of a deforming polyacrylamide solution is presented. It is shown that deformation induces effective hydrophobicity in the stretched polymer chains resulting in the formation of strong cooperative hydrogen bonding between the polymer chains. This finding has implications in providing insights into the mechanisms of the way spiders spin silk by rapidly deforming a freshly secreted protein solution. It has been argued that in a manner analogous to the model system showed here, it is likely that a rapid deformation induces phase separation of the solution into a polymer rich phase, which eventually forms the fiber. This work also naturally provides strategic hints for making silk like strong fibers by synthetic means at mild conditions.