From superhydrophobicity and water repellency to superhydrophilicity: smart polymer-functionalized surfaces

Abstract

pH-responsive surfaces, reversibly switching between superhydrophilicity and superhydrophobicity/water repellency, are developed by "grafting from" a pH-sensitive polymer onto a hierarchically micro/nano-structured substrate. We quantify the water repellency by investigating the restitution coefficient of water droplets bouncing off the surfaces. The water repellent state requires appropriate hydrophobicity of the functionalizing polymer as well as very low values of contact angle hysteresis.

Synthesis of pH-responsive tertiary amine methacrylate polymer brushes and their response to acidic vapour

“…27 The contact angle reported in the protonated state ( 60°) was somewhat lower than that observed in our study 55 Stratakis et al measured static contact angles, which allows more time for polymer chain reorganisation to expose the cationic amine groups compared to the advancing contact angle measurements used in our work. Acidic vapour response of PDPA homopolymer brushes 60 One aim of this work was to investigate the response of PDPA brushes to acidic vapours in surrounding atmosphere.…”

The superhydrophobicity of polymer surfaces: Recent developments

“…Other examples include ionisation of a carboxylic or amine ligand on an inorganic particle, 139 using poly 2-(dipropylamino)ethyl methacrylate (PDPAEMA), brushes, and switching with a gas. 140 A block copolymer of polyacrylic acid (PAA) and polystyrene (PS) can be switched by long exposure to water/dry heat from a patchy PAA surface to a hydrophobic PS surface. 141 Using a copolymer of 3- (acryloylthioureido) phenylboronic acid allowed switching to be carried out using sugar molecules.…”

Brushes of semiflexible polymers in equilibrium and under flow in a super-hydrophobic regime

“…This property is desirable for an important range of technological applications, such us self-cleaning surfaces, anti-fog, anti-corrosion, icephobicity and fluidic drag reduction [31,32]. Polymer brushes and coatings are also a way to obtain super-hydrophobic surfaces [5,33]. In recent years, new methodologies were developed to produce specific super-hydrophobic surfaces on small and large scales, suitable for basic research and production, respectively.…”

“…They find important applications in colloid stabilization, lubrication, and developments where friction [4], adhesion and wetting properties are important [1]. They are also used as coatings in "smart surfaces" to fine tune reversibly some property of an interface upon changes in external stimuli, for example, PH [5], temperature, solvent quality [6,7]. Brushes are at the forefront of recent developments, ranging from responsive bio-interphases, controlled drug-delivery and release systems, thin films and particles, which act as sensors of minute amounts of analytes [3,6].…”