ADHESION BETWEEN HYDROLYZED SURFACES OF POLY(DIMETHYLSILOXANE) NETWORKS

The JKR technique was used to study the adhesion hysteresis between hy drolyzed poly-(dimethylsiloxane), PDMS, networks. PDMS model networks were synthesized and then hydrolyzed for various lengths of time in a 0.1 M HCl aqueous solution. It was found that as the exposure time of the networks to the HCl solution increased, the adhesion hysteresis in creased. This hysteresis could be reduced by up to 80% by exposing the hydrolyzed networks to hexamethyldisilazane, which replaces the silan ol end-functionality with a trimethylsilyl group. This dramatic reduct ion of the hysteresis suggests that the bulk of the adhesion hysteresi s arises from a surface reconstruction reaction between silanol groups , We have also analyzed the unloading rate dependence of the adhesion hysteresis and found that it is probably due to the rate of bond disso ciation.