Amphiphilic Asymmetric Comb Copolymer with Pendant Pyrene Groups and PNIPAM Side Chains: Synthesis, Photophysical Properties, and Self-Assembly

An amphiphilic asymmetric comb polymer with pendant pyrene groups and poly(N-isopropylacrylamide) (PNIPAM) side chains was synthesized based on click chemistry and reversible addition−fragmentation chain transfer polymerization. Gel permeation chromatography, FTIR, and 1H NMR results all indicated successful synthesis of a well-defined comb polymer. The photophysical properties and self-assembly of the polymer in solution were studied by UV−vis spectroscopy, fluorescence technique, and transmission electron microscopy. The intensity ratio of the excimer peak (IE) to the monomer peak (IM) of the comb polymer in THF was used to monitor the formation of inter- or intramolecular excimers. At low polymer concentration, the value of IE/IM kept unchanged, indicating the formation of intramolecular excimer; at high polymer concentration, the value increased rapidly with concentration because of the formation of intermolecular excimer. The change of the intensity ratio of the first to the third vibronic band (I1/I...