Covalently attached liquids provide a liquid-liquid surface interaction for contacting contaminants, typically achieved through use of a polydimethylsiloxane linear polymer bound to the surface at one end. The attached dimethylsiloxane polymer chain retains liquid-like mobility through bending and rotational motions, distinguishing the coatings from those formed by crosslinked polydimethylsiloxane or branched polymer chains. Here, covalently attached liquids are reviewed and their potential for application as topcoat treatments is discussed. This review focuses on a new use scenario: prevention of chemical contamination. When allowed to age in place, chemical contaminants tend to penetrate into painted surfaces. Standard decontamination processes can fail to remove the chemicals within the paint layer, resulting in secondary exposure hazards when environmental conditions change. Covalent liquid coatings provide repellency and shedding behaviors. This review highlights the failure of typical wetting evaluations in predicting performance for the new application as well as the potential of the coatings in enhancing chemical resistance for painted surfaces. Potential methods for further improvements are also discussed. Published 2020. This article is a U.S. Government work and is in the public domain in the USA

Broadly nanoporous silicas and their composites comprise an extensive space in the literature with research examining silicas as: adsorbents for separating gases, as well as supports for various materials including catalysts, nanoparticles, sensors, porous materials, enzymes, and drugs. This chapter focuses on gas-phase applications of these materials and is organized into three sections: (1) synthesis steps to produce such materials; (2) isotherms and diffusion in silica materials; and (3) composite materials and associated adsorption behaviors.

Porous carbon is becoming an important and promising high-surface-area scaffold material for various energy-based applications including catalysis. Here we demonstrate the growth of urchin-like platinum nanoparticles (PtNPs) on carbon monoliths derived from basswood that work as catalysts for micro underwater vehicle (MUV) propulsion via H2O2 decomposition. The carbon monoliths were constructed of natural basswood that was carbonized in argon (Ar) and subjected to a subsequent CO2 activation process that rendered the material into a hardened 3D porous activated carbonized wood (ACW) with inner channel voids measuring 10-70 mu m in diameter. The PtNP nano-urchins (500 nm or less in total diameter, with individual nanospikes measuring 3-5 nm in diameter) form on the ACW via a facile electroless and template-free chemical deposition approach that utilizes the reduction of chloroplatinic acid. The developed PtNP-ACW hybrid material exhibited higher catalytic efficiency as compared to previously reported platinum (Pt) catalysts with a low activation energy of 18.9 +/- 2.5 kJ mol(-1) for H2O2 decomposition. The catalyst also proved useful in an important energy application by its ability to rapidly decompose H2O2 fuel and generate O-2 gas for propulsion of a 3D printed MUV prototype. The PtNP-ACW catalysts weighing only 0.14 g generated a propulsion thrust of 230 mN, which is sufficient to power MUVs. The natural wood derived carbon scaffolds significantly reduce the overall cost as compared to other carbon-based catalysts such as carbon nanotubes or graphene without reducing catalytic efficiency. Hence, such catalysts act as a stepping stone for potential low cost and sustainable power for burst thrust operation of MUVs.

A microwave deposition technique for silanes, previously described for production of oleophobic fabrics, is adapted to provide a fabric support material that can be subsequently treated by dip coating. Dip coating with a sol preparation provides a supported porous layer on the fabric. In this case, the porous layer is a porphyrin functionalized sorbent system based on a powdered material that has been demonstrated previously for the capture and conversion of phosgene. A representative coating is applied to cotton fabric at a loading level of 10 mg/g. This coating has minimal impact on water vapor transport through the fabric (93% of the support fabric rate) while significantly reducing transport of 2-chloroethyl ethyl sulfide (CEES) through the material (7% of support fabric rate). The described approaches are suitable for use with other fabrics providing amine and hydroxyl groups for modification and can be used in combination with other sol preparations to produce varying functionality.

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L −1 .

Biodiesel is produced by transesterification of animal fat, vegetable oil, or waste cooking oil with alcohol. After production costs, the economic viability of biodiesel is dependent on what steps are necessary to remove impurities following synthesis and the effectiveness of quality control analysis. Solid-phase extraction offers a potentially advantageous approach in biodiesel processing applications. Nanoporous scaffolds were investigated for adsorption of glycerol, a side product of biodiesel synthesis that is detrimental to engine combustion when present. Materials were synthesized with varying pore wall composition, including ethane and diethylbenzene bridging groups, and sulfonated to promote hydrogen bonding interactions with glycerol. Materials bearing sulfonate groups throughout the scaffold walls as well as those post-synthetically grafted onto the surfaces show notably superior performance for uptake of glycerol. The sorbents are effective when used in biodiesel mixtures, removing greater than 90% of glycerol from a biodiesel preparation.

Physical protection of nucleic acids from the environment for improved stability through encapsulation or adsorption has been reported using various materials, including liposomes, metal particles, mesoporous silica nanoparticles, and polymers. In an extension of that approach, our previous study demonstrated the potential of mesoporous silica nanoparticles with and without covalently attached stabilizing reagents, such as sugar and bovine serum albumin, for improving the stability of RNA. The goal of the current study is to evaluate the potential of silicate sorbents bearing chemical functionalities for stabilization of nucleic acid targets. Materials offering charged groups, metal chelating sites, and π-bonding sites are considered. Adsorption and elution of RNA, DNA, and single stranded DNA (ssDNA) are evaluated as is subsequent elution of the bound target. A sorbent functionalized with primary amine groups showed promising results for RNA and ssDNA stabilization. The impact of the sorbents on long term viability the targets is also evaluated. Storage of adsorbed targets at room temperature and 37∘C over a period of 200 d indicates the potential for stabilization of RNA and ssDNA using several of the functionalities. None of the sorbents improved the stability of DNA either under room temperature or 37∘C storage.

: This effort focused on development of a combined storage and delivery system intended to offer much-needed stability to biomolecules, especially DNA and RNA. The goal was to provide stabilization methods for reagents and targets in order to allow for a wider range of applications through utilization of organized porous materials as scaffolds for their encapsulation. This report details the synthesis of solid support materials, selection of stabilization components, and development of methods for their application. Design considerations focused on control of interactions with the nucleic acids that result in degradation. Over the course of the effort, the potential for adsorption of RNA, DNA, and ssDNA onto porous organosilicate sorbents with and without additional stabilizing reagents was demonstrated. Improved binding capacities were achieved with sorbents using chemical functionalities rather than proteins and sugars. These sorbents were found to provide similar improvements in stability to the traditional stabilization compounds. The materials were further shown to provide capture and subsequent stabilization of targets from a complex solution.

The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. Herein we develop high-aspect ratio (150:1), multiwalled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H2O2). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 μm) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation energy of 26.96 kJ mol(-1) capable of producing a thrust of 0.209 ± 0.049 N from 50% [w/w] H2O2 decomposition within a compact reaction chamber of eight Pt-CNT-MMs in series.

Platinum nanourchins supported on microfibrilated cellulose films (MFC) were fabricated and evaluated as hydrogen peroxide catalysts for small-scale, autonomous underwater vehicle (AUV) propulsion systems. The catalytic substrate was synthesized through the reduction of chloroplatinic acid to create a thick film of Pt coral-like microstructures coated with Pt urchin-like nanowires that are arrayed in three dimensions on a two-dimensional MFC film. This organic/inorganic nanohybrid displays high catalytic ability (reduced activation energy of 50-63% over conventional materials and 13-19% for similar Pt nanoparticle-based structures) during hydrogen peroxide (H2O2) decomposition as well as sufficient propulsive thrust (>0.5 N) from reagent grade H2O2 (30% w/w) fuel within a small underwater reaction vessel. The results demonstrate that these layered nanohybrid sheets are robust and catalytically effective for green, H2O2-based micro-AUV propulsion where the storage and handling of highly explosive, toxic fuels are prohibitive due to size-requirements, cost limitations, and close person-to-machine contact.