Grafting functional handles on to MEHPPV—Possible application for sensing

MEHPPV precursors containing dithiocarbamate groups along with methoxy units were used to initiate polymerisation of monomers, such as methyl acrylate and t-butyl acrylate, to yield grafted precursor systems. Typically, the grafting was done by UV irradiation, and the molecular weight of the grafted precursor polymer was seen to increase with exposure time. The t-butyl acrylate-grafted precursors were converted to the conjugated MEHPPV derivative by acid-catalysed elimination of the methoxy groups, during which time the hydrolysis of the t-butyl groups also occurred resulting in a hydrophilic MEHPPV with poly(acrylic acid) graft chains. These grafted MEHPPV derivatives were soluble in aqueous base as well as alcohols. Fluorescence spectroscopic studies indicated that these acrylic acid-grafted MEHPPV derivatives were very sensitive to analyte like methyl viologen.