pH-responsive host–guest polymerization and blending

Abstract

In this work, we demonstrate – in two different settings – the potential of the recognition motif made by tetraphosphonate cavitand/N-methyl ammonium salt for the development of supramolecular polymer chemistry. In the first part a novel pH sensitive supramolecular homopolymer was assembled by proper design of the corresponding monomer, and monitoring the self-assembling process by several analytical tools, including NMR spectroscopy and light scattering techniques. These measurements provided the evidence for the formation of the homopolymer and its pH responsiveness. In the second study, the two recognition groups – tetraphosphonate cavitand (Host) and sarcosine hydrochloride (Sarc) – introduced in polystyrene (PS–Host) and poly(butyl methacrylate) (PBMA–Sarc) respectively, led to the mixing of the two otherwise immiscible polymers thanks to the energetically favourable host–guest interactions between the polymer chains. The polymer blending was verified by the presence of a single glass transition temperature (T_g) and showed its homogeneous morphology by atomic force microscopy (AFM).