INVESTIGATION OF ADHESION HYSTERESIS IN POLY(DIMETHYLSILOXANE) NETWORKS USING THE JKR TECHNIQUE

The JKR technique was used to determine the source and nature of the a dhesion hysteresis present in modified poly(dimethylsiloxane) (PDMS) n etworks. As controlled excess amounts of the tetrafunctional crosslink er were added to the networks, the adhesion hysteresis increased. It w as found that by poisoning the catalyst with a thiol the hysteresis co uld be significantly lowered, and completely removed in some cases. We believe that the adhesion hysteresis in this system stems from a comp lexation between the excess crosslinker and the catalyst. We found tha t the work of adhesion in this case is a function of the unloading rat e. The unloading rate dependence of this chemical adhesion hysteresis was attributed to the rate of bond dissociation. (C) 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2129-2139, 1998.