Controllable layer-by-layer assembly of PVA and phenylboronic acid-derivatized chitosan

• The phenylboronic acid derivatized chitosan was prepared by EDC/NHS method.
• Self-assembly multilayers of chitosan–PBA and polyvinyl alcohol were built.
• The pH can be used as a switch to turn the self-assembly on or off.

Phenylboronic acid-derivatized chitosan (chitosan–PBA) were prepared by grafting small molecules bearing phenylboronic acid groups onto chitosan with N-hydroxysuccinimide (NHS) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) as a coupling reagent pair. Self-assembly multilayer thin films of chitosan–PBA and poly(vinyl alcohol) were subsequently produced under pH control on supporting surfaces, either a silicon wafer or polystyrene latex particles. The driving force of the self-assembly was the ester formation of phenylboronic acid containing polymers with PVA, which can be “turned off” by simple pH control.