Self‐Assembled Monolayers of a Malachite Green Derivative: Surfaces with pH‐ and UV‐Responsive Wetting Properties

Abstract

Surfaces that respond to pH and UV stimuli are fabricated from self‐assembled monolayers (SAMs) of a malachite green derivative on a rough surface (see figure). The wetting properties of the SAMs exhibit an uncommon response to pH and UV illumination, and range from superhydrophobicity to superhydrophilicity.

Tuning the Amphiphilicity of Building Blocks: Controlled Self‐Assembly and Disassembly for Functional Supramolecular Materials

“…This dual-tunable on/off switch broadens the insights for the fabrication of new wettingcontrolled stimuli materials. [114] …”

Supramolecular Polymers as Surface Coatings: Rapid Fabrication of Healable Superhydrophobic and Slippery Surfaces

“…[ 13 ] For the effective fabrication of such non-wetting surfaces, the interplay of surface energy and surface roughness is of critical importance and a variety of chemical and physical methods have been explored for the fabrication of suitable rough low-surface-energy coatings, including lithography, [ 14 ] chemical vapor deposition, [ 15 ] plasma techniques, [ 16 ] chemically modifi ed monolayers, [ 17 ] electrochemical methods, [ 18 ] sol-gel processes [ 19 ] as well as, more recently, the breath-fi gure technique (BFT). [ 20 ] However, these methods often require elaborate syntheses, fabrication protocols and/or specialized equipment so that a continuing need exists for simple, fast and low-cost fabrication approaches for the preparation of artifi cial non-wetting surfaces.…”

A Smart Superwetting Surface with Responsivity in Both Surface Chemistry and Microstructure

“…[14] So far, as mentioned above,only single surface chemistry or microstructure can be changed for wetting control. This imperfection significantly limits their controllability,wetting performance,and applications.F or instance,a st ot hose surfaces with responsive chemistry, [7][8][9][10] the microstructures are static,w hich offers ac onstant surface roughness;t hus,l imited wetting performances can be achieved as the surface chemistry is varied (generally,s urfaces with high surface roughness show superhydrophobicity/superhydrophilicity switching and those with low surface roughness display hydrophobicity/hydrophilicity transition). Fort hose PDMS surfaces with tunable microstructure, [11] the wetting variation is restricted in an arrow range between the superhydrophobicity and general hydrophobicity,s ince the surface chemistry is constant.…”

“…Recently,smart surfaces with switchable wettability have been extensively researched owing to their wide applications, [1,2] such as controllable oil/water separation, [3] cell capture/release, [4] bio-detection, [5] and so on. [6] Generally, these surfaces can be divided into two kinds:one kind is those with responsive surface chemistry,for example,temperatureresponsive poly(N-isopropylacrylamide) (PNIPAAm) coated silicon substrates, [7] pH-responsive carboxylic acid modified gold substrate, [8] solvent-responsive polymer brushes, [9] and some other stimuli-responsive systems,i ncluding ions,g as, electron, photo,a nd so on; [10] the other kind is those with tunable surface microstructure under external stretching, curving, or magnetic driving, [11] such as pillar structured polydimethylsiloxane (PDMS). However,o na ll these surfaces,o nly as ingle surface microstructure or chemistry can be controlled;s urfaces that with responsivity in both surface chemistry and microstructure have never been reported.…”