Percolation view of Novolak dissolution .9. Deuterium isotope effect on dissolution rate

A commercial Novolak resin was partially (OH groups) deuterated, and the dissolution rate of the deuterated material in 0.1 N solutions of KOD, NaOD, and LiOD in D2O was measured. The dissolution of the deuterated systems is considerably slower than that of the corresponding protonated systems. In both cases the dissolution rate depends on the nature of the base cation, and it is in fact a linear function of the reciprocal cross section of the ions. These results are-compatible with the view that the rate-determining step in Novolak dissolution is the deprotonation of phenol groups at the interface of the penetration zone with the resin matrix. The dissolution of deuterated Novolak in deuterated developers is strongly affected by the presence of salts of the base cations, in a manner similar to that of the protonated systems investigated in refs 1 and 2.