Controlling the wettability of plastic by thermally embedding coated aluminium oxide nanoparticles into the surface

Abstract

Nanoparticle embedding into the surface of plastics provides an effective anchor that improves the durability of coatings formed from functionalized nanoparticles. Coatings formed from thermally embedded particles show superior wear resistance relative to coatings formed from non-embedded particles. As a consequence of this, embedded nanoparticles functionalized with hydrophilic and hydrophobic carboxylates are better suited for controlling the wettability of plastics than when the nanoparticles are deposited onto the plastic under ambient conditions. Experiments 2Carboxylate-functionalized Al2O3 nanoparticles were embedded into ethylene vinyl acetate through spray coating the particles onto the substrate during heating. Sonication was used to remove excess particles that did not become embedded into the material. Coatings formed from the embedded particles were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive x-ray spectroscopy (EDX), and x-ray photoelectron spectroscopy (XPS).The wettability of the coatings was characterized using static and dynamic contact angle (CA) measurements to measure the apparent water contact angles, and sliding angle measurements, whilst the durability of the coatings was studied using scratch testing, tape peel tests, and abrasion tests.The build-up of fog on the substrates was also studied through exposing the surfaces to water vapour. FindingsThermal embedding of the particles into the surface of the plastic was observed to occur when the material was heated to temperatures around its melting temperature. AFM and SEM showed that plastic embedded with the nanoparticles possessed a morphology that was substantially rougher than the untreated plastic. CA measurements showed that plastic embedded with hydrophobic isostearate functionalized nanoparticles was highly hydrophobic and displayed a CA of approximately 152 o . Dynamic CA measurements and sliding angle measurements revealed that plastic embedded with the isostearate functionalized nanoparticles showed petal-like wetting behavior. Furthermore, it was observed that the CA of the plastic could be varied from highly hydrophobic to highly hydrophilic through embedding varying amounts of isostearate and hydrophilic 2-[2-(2methoxyethoxy)ethoxy]acetate functionalised Al2O3 nanoparticles into the surface of the material. Scratch testing showed that thermally embedding the nanoparticles into the plastic substantially improved their abrasion resistance, relative to when the nanoparticles are deposited onto the nonheated material. This methodology indicates that embedding nanoparticles into plastics creates 3 durable coatings that can display variable wettability. Consequently, this methodology could be useful in applications where it is desirable to keep plastics dry, such as for food packaging or medical devices.

Hybrid Hydrocarbon/Fluorocarbon Nanoparticle Coatings for Environmentally Friendly Omniphobic Surfaces

“…The loading of the carboxylic acids onto the nanoparticles was studied through TGA. Weight losses above 300 °C were attributed to the removal of chemically adsorbed carboxylates from the particles, in line with what we have observed in our previous studies. ,− Grafting densities were calculated using the method that we have discussed in our earlier publications. ,, It was observed that the grafting density of stearate onto aluminum oxide was saturated when it reached a value of about 1.2 nm –2 (Table ). Unsaturated surfaces were observed when the particles were immersed in solutions where the stearic acid concentration was below 5 mM.…”

Research progress on eco-friendly superhydrophobic materials in environment, energy and biology

“…4.2.4 Others. In addition to the common materials described above, paraffins, metal, 127,128 metal oxides, metal salts [129][130][131][132] and alkyl mercaptan can also be used to prepare superhydrophobic materials. Paraffin is a common material with low surface energy.…”

Interaction between Biofilm Formation, Surface Material and Cleanability Considering Different Materials Used in Pig Facilities—An Overview

“…One method to prevent bacterial adhesion is changing the material surface characteristics [28]. The literature has suggested different methods for modifying the hydrophobicity of different types of materials, such as chemical change of hardened cement pastes (HCP) [73], mortar [53], low-density polyethylene (LDPE) [74], thermal change (termorretification) of plywood [61] and the addition of metal particles on plastics [56,57].…”