Thermodynamics of Electrochemical Marine Inorganic Carbon Removal.

In recent years, marine carbon removal technologies have gained attention as a means of reducing greenhouse gas concentrations. One family of these technologies is electrochemical systems, which employ Faradaic reactions to drive alkalinity-swings and enable dissolved inorganic carbon (DIC) removal as gaseous CO or as solid minerals. In this work, we develop a thermodynamic framework to estimate upper bounds on performance for Faradaic DIC removal systems.

Enhanced Electrostatic Dust Removal from Solar Panels Using Transparent Conductive Nano-Textured Surfaces.

Dust accumulation on solar panels is a mjor operational challenge faced by the photovoltaic industry. Removing dust using water-based cleaning is expensive and unsustainable. Dust repulsion via charge induction is an efficient way to clean solar panels and recover power output without consuming any water.

Hierarchically conductive electrodes unlock stable and scalable CO electrolysis.

Electrochemical CO reduction has emerged as a promising CO utilization technology, with Gas Diffusion Electrodes becoming the predominant architecture to maximize performance. Such electrodes must maintain robust hydrophobicity to prevent flooding, while also ensuring high conductivity to minimize ohmic losses. Intrinsic material tradeoffs have led to two main architectures: carbon paper is highly conductive but floods easily; while expanded Polytetrafluoroethylene is flooding resistant but non-conductive, limiting electrode sizes to just 5 cm.

Crystal Patterning from Aqueous Solutions via Solutal Instabilities.

Fluid instabilities can be harnessed for facile self-assembly of patterned structures on the nano- and microscale. Evaporative self-assembly from drops is one simple technique that enables a range of patterning behaviors due to the multitude of fluid instabilities that arise due to the simultaneous existence of temperature and solutal gradients. However, the method suffers from limited controllability over patterns that can arise and their morphology.

Biofilm formation of Pseudomonas aeruginosa in spaceflight is minimized on lubricant impregnated surfaces.

The undesirable, yet inevitable, presence of bacterial biofilms in spacecraft poses a risk to the proper functioning of systems and to astronauts' health. To mitigate the risks that arise from them, it is important to understand biofilms' behavior in microgravity. As part of the Space Biofilms project, biofilms of Pseudomonas aeruginosa were grown in spaceflight over material surfaces.

Reducing Cancer Cell Adhesion using Microtextured Surfaces.

For the past century, trypsin has been the primary method of cell dissociation, largely without any major changes to the process. Enzymatic cell detachment strategies for large-scale cell culturing processes are popular but can be labor-intensive, potentially lead to the accumulation of genetic mutations, and produce large quantities of liquid waste. Therefore, engineering surfaces to lower cell adhesion strength could enable the next generation of cell culture surfaces for delicate primary cells and automated, high-throughput workflows.

Self-ejection of salts and other foulants from superhydrophobic surfaces to enable sustainable anti-fouling.

A recently discovered phenomenon in which crystalline structures grown from evaporating drops of saline water self-eject from superhydrophobic materials has introduced new possibilities for the design of anti-fouling materials and sustainable processes. Some of these possibilities include evaporative heat exchange systems using drops of saline water and new strategies for handling/processing waste brines. However, the practical limits of this effect using realistic, non-ideal source waters have yet to be explored.

Enhancing Protein Crystal Nucleation Using In Situ Templating on Bioconjugate-Functionalized Nanoparticles and Machine Learning.

Although protein crystallization offers a promising alternative to chromatography for lower-cost protein purification, slow nucleation kinetics and high protein concentration requirements are major barriers for using crystallization as a viable strategy in downstream protein purification. Here, we demonstrate that nanoparticles functionalized with bioconjugates can result in an in situ template for inducing rapid crystallization of proteins at low protein concentration conditions. We use a microbatch crystallization setup to show that the range of successful crystallization conditions is expanded by the presence of functionalized nanoparticles.

Dynamics of an impacting emulsion droplet.

Emulsions are widely used in agriculture where oil-based pesticides are sprayed as an emulsion. However, emulsion droplets can bounce off hydrophobic plant surfaces, leading to major health and environmental issues as pesticides pollute water sources and soils. Here, we report an unexpected transition from bouncing to sticking to bouncing as the droplet impact speed increases.

Electrostatic dust removal using adsorbed moisture-assisted charge induction for sustainable operation of solar panels.

Dust accumulation on solar panels is a major challenge, as it blocks a large portion of sunlight. Solar panels are therefore cleaned regularly using large quantities of pure water. Consumption of water for cleaning, especially in deserts, poses a substantial sustainability challenge.

Impact of Bubbles on Electrochemically Active Surface Area of Microtextured Gas-Evolving Electrodes.

The adverse effects of electrochemical bubbles on the performance of gas-evolving electrodes have been extensively studied. However, the ways in which bubbles dynamically alter the electrochemically active surface area during bubble evolution are not well understood. Here, we study hydrogen evolution at industrially relevant current densities by using controlled microtexture to examine this fundamental relationship.

Transient Effects Caused by Gas Depletion during Carbon Dioxide Electroreduction.

The novel use of carbon dioxide (CO) electroreduction to generate carbon-based products which do not contribute to the greenhouse effect has promoted the vision of carbon dioxide as a renewable feedstock for future clean fuel production. Depending on the material choice for the electrocatalysis, a certain variety of products is expected from the carbon dioxide reduction reaction (CO2RR). However, as the CO concentration in areas close to the working electrode (relative to the diffusive boundary layer) decreases as it is being consumed and transformed into other products, the generation of H is favored to the detriment of CO electroreduction.

Phase Change Dispersion Made by Condensation-Emulsification.

Cooling processes require heat transfer fluids with high specific heat capacity. For cooling processes below 0 °C, water has to be diluted with organic liquids to prevent freezing, with the undesired effect of reduced specific heat capacity. Phase change dispersions, PCDs, consist of a phase change material, PCM, being dispersed in a continuous phase.

Self-Propulsion of Boiling Droplets on Thin Heated Oil Films.

We report on the self-propulsion of boiling droplets which, despite their contact with viscous, immiscible oil films, attain high velocities comparable to those of levitating Leidenfrost droplets. Experiments and model reveal that droplet propulsion originates from a coupling between seemingly disparate short and long timescale phenomena due to microsecond fluctuations induced by boiling events at the droplet-oil interface. This interplay of phenomena leads to continuous asymmetric vapor release and momentum transfer for high droplet velocities.

Levitation of fizzy drops.

As first described by Leidenfrost, liquid droplets levitate over their own vapor when placed on a sufficiently hot substrate. The Leidenfrost effect not only confers remarkable properties such as mechanical and thermal insulation, zero adhesion, and extreme mobility but also requires a high energetic thermal cost. We describe here a previously unexplored approach using active liquids able to sustain levitation in the absence of any external forcing at ambient temperature.

Crystal critters: Self-ejection of crystals from heated, superhydrophobic surfaces.

Mineral or crystal fouling (the accumulation of precipitants on a material and damage associated with the same) is a pervasive problem in water treatment, thermoelectric power production, and numerous industrial processes. Growing efforts have focused on materials engineering strategies (e.g.

Differences between Colloidal and Crystalline Evaporative Deposits.

Evaporative deposits from drops are widely studied due to their numerous applications in low-effort self-assembly, including for inkjet printing, microscale separations, and sensing/diagnostics. This phenomenon has been broadly explored for drops containing suspended colloidal particles but has been less quantified for drops with dissolved solutes. When a drop of solute/solvent mixture is evaporated on a substrate, nonvolatile solutes become supersaturated as the solvent evaporates, which then leads to crystal nucleation at the substrate-drop contact line.

Enhancing the Injectability of High Concentration Drug Formulations Using Core Annular Flows.

Highly concentrated biological drug formulations would offer tremendous benefits to global health, yet they cannot be manually injected using commercial syringes and needles due to their high viscosities. Current approaches to address this problem face several challenges such as crosscontamination, high cost, needle clogging, and protein inactivation. This work reports a simple method to enhance formulation injectability using a core annular flow, where the transport of highly viscous fluids through a needle is enabled by coaxial lubrication by a less viscous fluid.

Author Correction: Enhancing droplet deposition through in-situ precipitation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Lubricant-Impregnated Surfaces for Mitigating Asphaltene Deposition.

Asphaltenes are heavy aromatic components of crude oil. Their complex chemical makeup-an aromatic core surrounded by aliphatic side chains-enables them to adhere to most surfaces. Their buildup in pipes can result in clogging and lead to interruption of production operations and expensive mechanical cleaning.

Asphaltene Adsorption on Functionalized Solids.

Asphaltenes, heavy aromatic components of crude oil, are known to adsorb on surfaces and can lead to pipe clogging or hinder oil recovery. Because of their multicomponent structure, the details of their interactions with surfaces are complex. We investigate the effect of the physicochemical properties of the substrate on the extent and mechanism of this adsorption.

Low-Voltage Surface Electrocoalescence Enabled by High-K Dielectrics and Surfactant Bilayers for Oil-Water Separation.

Processes for separating oil-water mixtures are critical to operations in energy and water. However, existing separation methods pose efficiency limitations as well as environmental and safety challenges. Here, we present a low-voltage surface electrocoalescence approach that triggers coalescence of surfactant-stabilized emulsions by combining high-K dielectrics with surfactant bilayers.

Evaporative Crystallization of Spirals.

Spiral motifs are pervasive in nature, art, and technology due to their functional property of providing compact length. Nature is particularly adept at spiral patterning, and yet, the spirals observed in seashells, hurricanes, rams' horns, flower petals, etc. all evolve via disparate physical mechanisms.

Waterbowls: Reducing Impacting Droplet Interactions by Momentum Redirection.

Superhydrophobic surfaces can dramatically reduce the transport of mass or energy from impacting droplets by making them bounce off. Such transport processes are dependent on both the contact time and the contact area between the drop and the surface. To reduce transport, recent studies have focused on reducing the contact time.