Miscibility of poly(para-phenylene vinylene) model compounds with polycarbonate studied by solid-state NMR

Abstract

Wittig synthesis of 2,5-dimethoxy-1,4-bis(2-(3,4,5-trimethoxyphenyl)ethenyl)benzene (MPV) was shown by high-temperature GC/MS to consist of about 34% cis,cis-, 46% trans, cis- and 20% trans, trans-configurations. The configurational mixture blended with polycarbonate (PC) results in homogeneous, intimate mixing at the molecular level for all investigated weight ratios MPV/PC (up to 60/40%). This follows from (i) the occurrence of cross-peaks in two-dimensional H-1 combined rotation and multiple pulse NMR spectroscopy (CRAMPS), and (ii) the observation of one common proton spin-locking relaxation time (T1rhoH) for all protons in the mixture together with a linear variation of these T1rhoH values as a function of the mixture composition.