The conformation of poly(3-dodecyl thiophene) within methacrylic polymer matrix

Blends of poly(3-dodecyl thiophene) (PDDT) with poly(methyl methacrylate), poly(butyl methacrylate) (PBMA), and poly(methyl methacrylate-co-butyl meth acrylate) (PMMA/PBMA) were studied by polarization optical microscopy, atom ic-force microscopy, and absorption spectroscopy and were modeled using mol ecular dynamics (MD) simulations. The observed thermochromic transitions ar e shown to be host-matrix dependent, with PDDT/PBMA absorption spectra diff ering substantially from pristine PDDT. The dispersion of PDDT within PBMA matrix is observed to be greater than in the other host polymers. MD calcul ations of both individual PDDT molecules and molecular aggregates suggest t hat the distribution of dihedral angles present in the PDDT backbone is the narrowest for aggregates of PDDT embedded within a polymer matrix. (C) 199 9 John Wiley & Sons, Inc.