Microporous materials derived from two- and three-dimensional hyperbranched conjugated polymers by thermal elimination of substituents

Abstract

Symmetrical and multivalent monomers having thermally degradable alkoxyl groups such as 1,3,5-triethynylbenzene and tetra(4-bromophenyl)silane derivatives were polymerised by certain appropriate methods, i.e. Hay or Sonogashira coupling, which gave hyperbranched poly(phenylenebutadiynylene)s and poly(phenyleneethynylene)s having rigid macrocyclic frameworks in high yields. By heat treating the polymers at about 400 °C, the degradable side chains were selectively eliminated resulting in microporous pyrolytic polymers that showed surface areas of ca. 800 m² g⁻¹. This result suggests that the spaces resulting from the elimination of the side chains contribute to the generation of the pores of the pyrolytic polymers. In addition, most of the pyrolytic polymers retained their microporosity after further heat treatments at 900 °C, affording microporous carbon.