Honeycomb-patterned film segregated with phenylboronic acid for glucose sensing

Phenylboronic acid (PBA)-functionalized materials have attracted considerable attention because of their potential applications in many fields. In this paper, we report a PBA-segregated honeycomb-patterned porous film (HPPF) for glucose sensing. Polystyrene-block-poly(acrylic acid-co-acrylamidophenylboronic acid) with different contents of PBA pendants was synthesized via atom transfer radical polymerization (ATRP) followed by a coupling reaction. PBA-functionalized HPPFs were then fabricated by the breath figure method. Results indicate that the composition of the copolymers and the relative humidity play key roles in pore size and regularity of the films. Using Alizarin Red S (ARS) that does not emit fluorescence itself as a fluorescent probe, it is confirmed that PBA pendants are mainly distributed at the pore wall, instead of at the outer surface of HPPFs. This distribution is caused by the segregation of hydrophilic PBA-blocks toward the condensed water droplets, which act as templates for the pore formation. Quartz crystal microbalance results demonstrate that the PBA-functionalized HPPFs show high sensitivity in glucose sensing, which is owing to the segregation of PBA pendants at the pore wall as well as the large specific surface area of the porous films.