Thin-Film Behavior of Poly(methyl methacrylates). 4. Stereocomplexation of Isotactic and Syndiotactic Poly(methyl methacrylate) at the Air-Water Interface

Under the proper conditions, a transition can be observed in compression isotherms of mixed monolayers of isotactic and syndiotactic poly(methyl methacrylate), which is shown to correspond to a pressure-induced stereocomplexation process between the isotactic and syndiotactic components, analogous to similar processes in solution or melt mixtures. The identity of the double-helical stereocomplex structures is confirmed by the distinct 2:1 (s-i) segmental stoichiometry observed, the dependence of the process on the stereoregularity of the components, and the infrared characteristics of transferred multilayers. The monolayer stereocomplex structures can be transferred to solid substrates to yield almost uniaxially oriented thin films. Following annealing treatments, these films were shown to possess melting points close to 190-degrees-C.