We have investigated the superhydrophobic behavior of coatings of polydimethylsiloxane (PDMS) and polystyrene (PS) on ZnO nanowire-arrays. PDMS produced a conformal coating on the ZnO nanowires due to high interfacial affinity between ZnO and PDMS, resulting in a large water contact angle of 168.0 degrees (compared to 108.8 degrees for planar PDMS surfaces) and droplet roll-off angles that were too small to measure. The superhydrophobicity of these coatings is among the largest reported for any polymeric coating. PS instead preferentially coated the bases of the ZnO nanowires and valleys between nanowires due to low interfacial affinity between ZnO and PS, resulting in a water contact angle of 149.3 degrees (compared to 90.5 degrees for planar PS surface) and droplet roll-off angles of 5 degrees-8 degrees. If, however, the ZnO nanowires were etched away after PS deposition, hollow tube-like nanostructures of PS were left behind, and exhibited a water contact angle of 164.3 degrees and droplet roll-off angles of 1 degrees-2 degrees. These nanostructured PS coatings offer unique potential for food-safe superhydrophobic coatings because they consist only of PS without any inorganic components.

Wind tunnel experiments examined the coupled effects of relative humidity (RH) and surface and particle properties on aerodynamically induced resuspension. Hydrophilic glass spheres and hydrophobic polyethylene spheres similar to 20 mu m in diameter, with nanoscale surface features, were resuspended from hydrophilic glass, hydrophobic chemical agent resistant coating (CARC), and gold surfaces. Roughness of the glass and gold surfaces was on the nanoscale, whereas CARC surfaces had microscale roughness. Different particle-surface combinations yielded van der Waals interactions that varied by a factor of 4, but these differences had a relatively minor effect on resuspension. Wind tunnel RH was varied between 7% and 78%. Overall, RH affected the resuspension of hydrophilic particles on hydrophilic surfaces most strongly and that of hydrophobic particles on hydrophobic surfaces the least. For each particle-surface combination there was a threshold RH value below which resuspension rates were essentially constant and in good agreement with a dimensionless model of particle resuspension.Copyright (c) 2016 American Association for Aerosol Research

: Over the course of this program, the Center for Nanoscale Science and Engineering (CNSE) at North Dakota State University (NDSU) in partnership with Triton Systems, Inc. augmented its core materials science research capabilities to foster the development of next generation, antimicrobial coating technologies aimed at protecting US military personnel from exposure to hazardous biological agents in the battlefield. A key element to the success of this project was the development, early on, of a high-throughput biological screening workflow to enable combinatorial exploration of novel antimicrobial coating/treatment concepts. A number of different strategies based on reactive, functional oligomers containing quaternary ammonium salts (QAS) were investigated for their ability to impart antimicrobial properties to both fabrics (i.e., nylon and polyester) and other rigid materials (i.e., glass and metals) of relevance to the US military. One approach in particular, based on QAS-functional acrylates, was shown to be highly effective at generating broad-spectrum, antimicrobial treatments for polyester fabric using Triton Systems novel atmospheric pressure plasma deposition process (Invexus ). It is envisioned that these new antimicrobial technologies developed at NDSU will be harnessed by Triton Systems to produce efficacious and operationally functional products for the US military via their industrial scale, textile treatment line (RC1000 ).

Abstract : Novel additives for polymeric coatings have been developed based on modified hyperbranched polymers. The additives are polyfunctional and have been prepared to spontaneously segregate to the surface of the polymer in which they are dispersed. They ave been used to install active sites in polymeric films, with little or no change in the formulation, bulk properties, or application of the coating.

L’invention concerne des nanocomposites polymeriques comprenant soit de la silice, soit des particules d’oxyde metallique non lamellaires, ainsi que l’utilisation de ces nanocomposites polymeriques dans la couche centrale de stratifies et de films multicouches formant une barriere. Les nanocomposites polymeriques presentent d’importantes proprietes de barriere et une faible permeation aux gaz.

Different polymer nanocomposites were prepared during this study. The polymer matrix, the nanoclay type and loadings were systematically varied. Processing conditions (screw speed, configuration, and temperature profile) were varied as well in order to find the optimum conditions for nanocomposite synthesis. Dispersion and exfoliation of nanoclays in the polymer nanocomposites were characterized via XRD and TEM. Single and multi layer films were prepared initially in lab scale and characterized. Subsequently, a 62" multilayer blown film was made and laminated into a fabric for tent applications. The liner material was characterized for chemical agent (HD/GB) barrier properties, flame retardant, and mechanical properties. Results showed that the new liner material offers up to 72 hours protection against HD and GB chemical agents. The new tent liner material showed good heat sealability. A full M28 tent liner was manufactured at the end and submitted for further testing. This technology has the potential to realize immediate utilization in currently used tentage systems, as well as long-term feasibility for its transition to future programs, including the Joint Expeditionary Collective Protection (JECP) program.