Bioinspired broadband antireflection coatings on silicon wafers enabled by a polyimide-assisted self-masking technique.

Here we report a simple self-masking technique for fabricating bioinspired broadband antireflection coatings on both single-crystalline and multicrystalline silicon wafers with the assistance of a polyimide tape. Subwavelength-structured moth-eye nanopillars, which exhibit superior antireflection performance over a broad range of visible and near-IR wavelengths, can be patterned uniformly on the wafer surface by applying a chlorine-based reactive ion etching (RIE) process. The resulting random nanopillars show improved antireflection properties compared with ordered nanopillars templated by colloidal lithography under the same RIE conditions.

Chromogenic Photonic Crystal Detectors for Monitoring Small Molecule Diffusion at Solid-Solid Interfaces Using Stimuli-Responsive Shape Memory Polymers.

In situ monitoring of small molecule diffusion at solid-solid interfaces is challenging, even with sophisticated equipment. Here, novel chromogenic photonic crystal detectors enabled by integrating bioinspired structural color with stimuli-responsive shape memory polymer (SMP) for detecting trace amounts of small molecule interfacial diffusion are reported. Colorless macroporous SMP membranes with deformed macropores can recover back to the "memorized" photonic crystal microstructures and the corresponding iridescent structural colors when triggered by diffused small molecules.

Nanoconfinement of Carbon Dioxide within Interfacial Aqueous/Ionic Liquid Systems.

Nanoporous, gas-selective membranes have shown encouraging results for the removal of CO from flue gas, yet the optimal design for such membranes is often unknown. Therefore, we used molecular dynamics simulations to elucidate the behavior of CO within aqueous and ionic liquid (IL) systems ([EMIM][TFSI] and [OMIM][TFSI]), both confined individually and as an interfacial aqueous/IL system. We found that within aqueous systems the mobility of CO is reduced due to interactions between the CO oxygens and hydroxyl groups on the pore surface.

Transport and Energetics of Carbon Dioxide in Ionic Liquids at Aqueous Interfaces.

A major hurdle in utilizing carbon dioxide (CO) lies in separating it from industrial flue gas mixtures and finding suitable storage methods that enable its application in various industries. To address this issue, we utilized a combination of molecular dynamics simulations and experiments to investigate the behavior of CO in common room-temperature ionic liquids (RTIL) when in contact with aqueous interfaces. Our investigation of RTILs, [EMIM][TFSI] and [OMIM][TFSI], and their interaction with a pure water layer mimics the environment of a previously developed ultrathin enzymatic liquid membrane for CO separation.

Machine Learning Predictions of Simulated Self-Diffusion Coefficients for Bulk and Confined Pure Liquids.

Diffusion properties of bulk fluids have been predicted using empirical expressions and machine learning (ML) models, suggesting that predictions of diffusion also should be possible for fluids in confined environments. The ability to quickly and accurately predict diffusion in porous materials would enable new discoveries and spur development in relevant technologies such as separations, catalysis, batteries, and subsurface applications. In this work, we apply artificial neural network (ANN) models to predict the simulated self-diffusion coefficients of real liquids in both bulk and pore environments.

Symbolic regression development of empirical equations for diffusion in Lennard-Jones fluids.

Symbolic regression (SR) with a multi-gene genetic program has been used to elucidate new empirical equations describing diffusion in Lennard-Jones (LJ) fluids. Examples include equations to predict self-diffusion in pure LJ fluids and equations describing the finite-size correction for self-diffusion in binary LJ fluids. The performance of the SR-obtained equations was compared to that of both the existing empirical equations in the literature and to the results from artificial neural net (ANN) models recently reported.

Quantum Calculations of VX Ammonolysis and Hydrolysis Pathways via Hydrated Lithium Nitride.

Recently, lithium nitride (LiN) has been proposed as a chemical warfare agent (CWA) neutralization reagent for its ability to produce nucleophilic ammonia molecules and hydroxide ions in aqueous solution. Quantum chemical calculations can provide insight into the LiN neutralization process that has been studied experimentally. Here, we calculate reaction-free energies associated with the LiN-based neutralization of the CWA VX using quantum chemical density functional theory and ab initio methods.

Machine Learning-Based Upscaling of Finite-Size Molecular Dynamics Diffusion Simulations for Binary Fluids.

Molecular diffusion coefficients calculated using molecular dynamics (MD) simulations suffer from finite-size (i.e., finite box size and finite particle number) effects.

Manipulating the Amount and Structure of the Organic Matrix Affects the Water Compartments of Human Cortical Bone.

Being predictors of the mechanical properties of human cortical bone, bound and pore water measurements by magnetic resonance (MR) imaging are being developed for the clinical assessment of fracture risk. While pore water is a surrogate of cortical bone porosity, the determinants of bound water are unknown. Manipulation of organic matrix properties by oxidative deproteinization, thermal denaturation, or nonenzymatic glycation lowers bone toughness.

Self-assembled nanoparticle antireflection coatings on geometrically complex optical surfaces.

Here we report a simple and scalable electrostatics-assisted colloidal self-assembly technology for fabricating monolayer nanoparticle antireflection coatings on geometrically complex optical surfaces. By using a surface-modified glass volumetric flask with a long neck as a proof-of-concept demonstration, negatively charged silica nanoparticles with 110 nm diameter are electrostatically adsorbed on both the interior and exterior surfaces of the flask possessing positive surface charges. The self-assembled monolayer nanoparticle antireflection coatings can significantly improve light transmission through different regions of the flask with varied curvatures, as revealed by optical transmission measurements and numerical simulations using a simplified thin-film multilayer model.

Assessing glycation-mediated changes in human cortical bone with Raman spectroscopy.

Establishing a non-destructive method for spatially assessing advanced glycation end-products (AGEs) is a potentially useful step toward investigating the mechanistic role of AGEs in bone quality. To test the hypothesis that the shape of the amide I in the Raman spectroscopy (RS) analysis of bone matrix changes upon AGE accumulation, we incubated paired cadaveric cortical bone in ribose or glucose solutions and in control solutions for 4 and 16 weeks, respectively, at 37°C. Acquiring 10 spectra per bone with a 20X objective and a 830 nm laser, RS was sensitive to AGE accumulation (confirmed by biochemical measurements of pentosidine and fluorescent AGEs).