Mimicking the velcro system from nature for an alternative rubber/silica coupling system

Beside carbon black, silica becomes the most important filler for high-performance rubber products. However, unlike carbon black its surface properties are not favorable for providing satisfactory rubber/filler interactions. A significant amount of silanol groups present on the silica surface results in a considerably polar character, whereas most of rubbers exhibit a non-polar or relatively low-polar character. Because of this, various approaches towards different surface treatments of silica were made. The aim of this research is to introduce an alternative type of rubber/silica coupling inspired by the velcro system existing in nature. The bio-mimicking mechanism is based on physical entanglements and steric hindrance between mutually soluble (based on calculated solubility parameters): cross-linked and entangled rubber macromolecules – acting as molecular loops - and oligomer brushes grafted onto the silica surface – acting as molecular hooks. This results in the formation of supramolecular hooks-and-loops, a rubber/silica interphase fastener exhibiting reconnectable performance