When a pH-triggered nanopatterned shape transition drives the wettability of a hierarchically self-organized film: a bio-inspired effect of “sea Anemone”
Résumé
Hypothesis:Hierarchically structured surfaces including sensitive materials presents the advantage toexalt wettability variation due to the combination of micro structure effect directed by Cassie Baxterand/or Wenzel behaviour which is tuned by the surface energy variation of sensitive polymer films.Experiments:Herein is reported the synthesis and the hierarchical structuration of a pH sensitive diblockcopolymer P(S-stat-MMA)-b-P4VP with a pH-sensitive Poly 4-vinylpyridine P4VP block. Applying theBreath Figure method casting (minute time scale process), this diblock copolymer allows to obtain amicro porous honeycomb film while a wall nano-structuration due to self-assembly of diblock copolymeris observed.Findings:The pH-triggered wettability is studied and correlated with the morphology evolution of P4VPnano-domains investigated by AFM in a liquid cell. Indeed, a nano-dots to nano-rings/donuts transition ishighlighted when decreasing the pH below thepKa of the P4VP. This nano ‘‘sea Anemone” shape transi-tion induces the macroscopic changes of the wettability of a hierarchically self-organized honeycombfilm, explained by the protonation of P4VP chains inducing electrostatic repulsion and then hydrophilicsurface.
Origine : Fichiers produits par l'(les) auteur(s)
