Reversible molecular adsorption of free-standing nano-composite film made from boehmite and poly(acrylic acid)

A nano-composite film with reversible small molecules adsorption behavior was fabricated via layer-by layer (LbL) assembly of boehmite nano-particles and weak polyelectrolyte poly(acrylic acid) (PAA). Both electrostatic force and hydrogen bonding interaction were involved to fabricate the nano-composite thin film. Boehmite/PAA nano-composite thin film was further cross-linked with thermal treatment, which enhanced the stability of the film. When immersed into the basic solution, the thermal cross-linked film wholly detached from the substrate. And the dynamic cross-links such as hydrogen bonding and electrostatic interaction endowed the free-standing film reversible swelling/shrinking ability in response to pH variations at least five times. Furthermore, the free-standing Boehmite/PAA film showed reversible rhodamine B (RB) adsorption behavior, which could be utilized for controlled loading and releasing. (C) 2016 Elsevier B.V. All rights reserved.