Preview

PDF, English Download (106MB) | Terms of use

Abstract

Internal stress in molecular structures is increasingly appearing as a crucial I factor in determining functional properties at a large range of length scales. The present work has investigated the e ect of stress for two distinct molecular processes, chemical reactions and straining of a two-phase ber, using a highly interdisciplinary approach involving quantum-mechanical and nite element simulations. First, with the aim of better understanding the contribution of stress to reactivity, we discovered that kinetics of strain-promoted cycloadditions can be nely tuned by exploiting the reactants' stereoisomeric and regioselective states and thereby the strain coupled to the reaction. Secondly, at longer length scales, we dissected the contributions of stress to the mechanical properties of complex materials. Our simulations predict a stress-induced ordering in spider silk, which was validated by scattering experiments. Beyond the basic understanding of the investigated systems, the findings presented in this work open new scenarios for the possibility to enhance strain-dependent chemical reactivity and the mechanics of composite materials.