Tetraphenylthiophene-terminated poly(acrylic acid) as pH- and bio-sensors by the aggregation-induced emission property

Amphiphilic poly(acrylic acid) terminated with tetraphenylthiophene (TP) was prepared by atom transfer radical polymerization (ATRP) of t-butyl acrylate monomer, initiated by amino-functionalized TP, and the following by acid-catalyzed hydrolysis. With the hydrophobic TP terminal, a fluorophore with aggregation-induced emission (AIE) property, and the hydrophilic polymeric chain, the resulting polymer of TP-PAA is amphiphilic and self-assembled, through preferable hydrogen bond interactions among the carboxylic acid pedants, in water to form aggregates with strong AIE-related emission. The convenient dispersion of TP-PAA aggregates in water facilitated its applications as fluorescent sensor for pH value and for the natural protein of bovine serum albumin (BSA). Fluorescence variations in term of aggregation level of the TP terminals in different environments will be discussed in this study.