Fabrication of Zinc Substrate Encapsulated by Fluoropolyurethane and Its Drag-Reduction Enhancement by Chemical Etching

Abstract

A fluoropolyurethane-encapsulated process was designed to rapidly fabricate low-flow resistance surfaces on the zinc substrate. For the further enhancement of the drag-reduction effect, Cu2+-assisted chemical etching was introduced during the fabrication process, and its surface morphology, wettability, and flow-resistance properties in a microchannel were also studied. It is indicated that the zinc substrate with a micro-nanoscale roughness obtained by Cu2+-assisted nitric acid etching was superhydrophilic. However, after the etched zinc substrate is encapsulated with fluoropolyurethane, the superhydrophobic wettability can be obtained with a contact angle of 154.8° ± 2.5° and a rolling angle of less than 10°. As this newly fabricated surface was placed into a non-standard design microchannel, it was found that with the increase of Reynolds number, the drag-reduction rate of the superhydrophobic surface remained basically unchanged at 4.0% compared with the original zinc substrate. Furthermore, the prepared superhydrophobic surfaces exhibited outstanding reliability in most liquids.

Biological and Physiochemical Methods of Biofilm Adhesion Resistance Control of Medical-Context Surface

“…The recent research of modified antibiofouling polyurea coating reveals that the modified polyurea anti-biofouling coating indicates hydrophobic characteristic; the nano-titanium dioxide may generate reactive oxygen species to kill the bacteria; and the riblet surface textures formed by nano-titanium dioxide and even nano-zinc oxide are capable to perform anti-bacteria characteristics as well [98][99]. Not using the other chemical agent such as silver and organic solvent, is because the toxic effects could be observed at very low concentrations, bioaccumulation (removal capacity exceeded) and biomagnification (accumulation up the food chain/web) may also induce more toxic substance into organisms and environment.…”

Mechanisms and Control Measures of Mature Biofilm Resistance to Antimicrobial Agents in the Clinical Context

“…Typically, the anti-adhesion coating can prevent biofilm formation at its early stage, which should be more desirable in clinical settings. The anti-adhesion coating surface generally needs considerations for four characteristics, which includes chemical composition and reactivity, hydrophilic/hydrophobic wettability, surface textures, and surface charges . For example, the recent research obtained by Li et al reveals that the modified polyurea antibiofouling coating indicates a hydrophobic characteristic; the nanotitanium dioxide may generate reactive oxygen species to kill the bacteria, and the riblet surface textures formed by nanotitanium dioxide are able to enhance the drag reduction effect and the antibiofouling performance, as well.…”

Mini-Review of Biofilm Interactions with Surface Materials in Industrial Piping System

“…The main metals involved in these corrosion mechanisms are iron and manganese. The effect of bleaching agents does not last long enough in large circulating systems [ 62 ]. To allow sufficient residual bleach in the rest of the system, an excessive amount of bleach may be required in the rest of the system.…”