Tunable Wetting Mechanism of Polypyrrole Surfaces and Low-Voltage Droplet Manipulation via Redox

Abstract

This paper presents the experimental results and analyses on a controlled manipulation of liquid droplets upon local reduction and oxidation (redox) of a smart polymer-dodecylbenzenesulfonate doped polypyrrole (PPy(DBS)). The electrochemically tunable wetting property of PPy(DBS) permitted liquid droplet manipulation at very low voltages (-0.9 to 0.6 V). A dichloromethane (DCM) droplet was flattened upon PPy(DBS) reduction. It was found that the surface tension gradient across the droplet contact line induced Marangoni stress, which caused this deformation. Further observation of PPy(DBS)'s color change upon the redox process confirmed that the surface tension gradient was the driving force for the droplet shape change.

Tunable conjugated polymers for bacterial differentiation

“…The redox state altered the hydrophobicity of the polymer surfaces, but the impact of this effect varied due to the type of dopant. DBS-doped polymer showed a drastic change in hydrophobicity in the different redox states [67]. Comparing Figure 1.a and 2B shows some correlation between water contact angle and adhesion in some cases.…”

PANI nanowire film with underwater superoleophobicity and potential-modulated tunable adhesion for no loss oil droplet transport

“…21 Generally, PANI has three stable oxidation states, i.e., the fully reduced leucoemeraldine form (LEB), the half-oxidized emeraldine base (EB), and the fully oxidized pernigraniline form (PNB). 16,23,24 For instance, Wallance et al developed a strategy to achieve delivery of oil on polypyrrole (PPy) coated platinum mesh. When PANI is electrochemically reduced or oxidized, its properties change easily such as color, conductivity, chemical composition and wettability.…”

Recent Progress in Fabrication and Applications of Superhydrophobic Coating on Cellulose-Based Substrates

“…Superhydrophobic surfaces are responsive and switchable under circumstances, such as pH, light (UV, plasma, and laser), temperature, humidity and electrochemical treatments. All of these depend on the type of materials utilized for coating applications [191,192,193,194,195,196,197]. Moreover, the durability and breathability of anti-wetting surface is an important question we must address in order to broaden its practical applications.…”