Self-regulating bioinspired supramolecular photonic hydrogels based on chemical reaction networks for monitoring activities of enzymes and biofuels.

Inspired by the way many living organisms utilize chemical/biological reactions to regulate their skin and respond to stimuli in the external environment, we have developed a self-regulating hydrogel design by incorporating chemical reaction networks (CRNs) into biomimetic photonic crystal hydrogels. In this hydrogel system, we used host-guest supramolecular non-covalent bonds between beta-cyclodextrin (β-CD) and ferrocene (Fc) as partial crosslinkers and designed a CRN involving enzyme-fuel couples of horseradish peroxidase (HRP)/HO and glucose oxidase (GOD)/d-glucose, by which the responsive hydrogel was transformed into a glucose-driven self-regulating hydrogel. Due to the biomimetic structural color in the hydrogel, the progress of the chemical reaction was accompanied by a change in the color of the hydrogel.

Terahertz imaging for non-destructive porosity measurements of carbonate rocks.

Within the petrochemical industry, accurate measurement of microporosity and its distribution within core samples, particularly those from carbonate reservoirs, has garnered intense interest because studies have suggested that following primary and secondary depletion, a majority of the residual and bypassed oil may reside in these porosities. Ideally, the microporosity and its distribution would be determined accurately, quickly, and efficiently. Imaging techniques are commonly used to characterize the porosity and pores but accurate microporosity characterization can be challenging due to resolution and scale limitations.

Genesis of Nanogalvanic Corrosion Revealed in Pearlitic Steel.

Nanoscale, localized corrosion underpins billions of dollars in damage and material costs each year; however, the processes responsible have remained elusive due to the complexity of studying degradative material behavior at nanoscale liquid-solid interfaces. Recent improvements to liquid cell scanning/transmission electron microscopy and associated techniques enable this first look at the nanogalvanic corrosion processes underlying this widespread damage. Nanogalvanic corrosion is observed to initiate at the near-surface ferrite/cementite phase interfaces that typify carbon steel.

A rational approach towards selective ethylene oligomerization PNP-ligand design with an -triptycene functionality.

Novel PNP ligands bearing an -triptycene backbone were developed and evaluated for selective ethylene oligomerization. Upon activation with MMAO-3A, the pre-catalyst mixture containing Cr(acac)/ligand efficiently promotes ethylene tetramerization with remarkably high productivities (up to 1733 kg g h) and C olefin selectivities (up to 74.1 wt%).

Critical Packing Density of Water-Mediated Nonstick Self-Assembled Monolayer Coatings.

Nanoparticle-mineral surface interactions are relevant in many biological and geological applications. We have previously studied nanoparticle coatings based on closely packed bicomponent polyol-fluoroalkane self-assembled monolayers (SAMs) that can have tunable stickiness on calcite surfaces by changing the compositions of fluoroalkanes in SAMs, where the coatings show nonstick properties if fluoroalkanes can effectively perturb hydration layers on calcite surfaces. However, when applying coatings on nanoparticles, it can be challenging to predict the maximum achievable coating density.

Amorphous Fe(OH) Passivating CeO Nanorods: A Noble-Metal-Free Photocatalyst for Water Oxidation.

Noble-metal-free composites with good photocatalytic property are of great interest. Here, CeO nanorods composites loaded with amorphous Fe(OH) cocatalyst were designed and prepared via a secondary water bath at 100 °C. The as-synthesized CeO /amorphous Fe(OH) composites exhibited superior light photocatalytic activities compared to pure CeO , especially the sample with a loading time of 60 min.

Emergent slow dynamics of collapsed polymers flowing through porous media.

Using hydrodynamic simulations, we study the single polymers flowing through model porous media (close-packed colloidal crystal). In good solvent or high flow rates, the polymer transport is similar to gel electrophoresis, with size-dependent sieving for L_{c}/L≲1 and size-independent biased reptation for L_{c}/L≳1 (L_{c} is the polymer contour length and L is the diameter of colloids forming the porous media). Importantly, in bad solvent and low flow rates, the polymers show an extra window of size-dependent velocity for 1≲L_{c}/L≲2, where the polymer transport is controlled by a globule-stretch transition at pore throats, and the transport velocity is much slower than reptation.

Controlling water-mediated interactions by designing self-assembled monolayer coatings.

Engineered nanoparticles have been broadly used in biological and geological systems. Hydrophilic molecules such as polyols have been used as coatings on nanoparticle surfaces due to their good biocompatibility and solubility in saline water. However, polyol coatings can cause huge retention of nanoparticles when encountering mineral surfaces.

High-temperature high-pressure microfluidic system for rapid screening of supercritical CO foaming agents.

CO foam helps to increase the viscosity of CO flood fluid and thus improve the process efficiency of the anthropogenic greenhouse gas's subsurface utilization and sequestration. Successful CO foam formation mandates the development of high-performance chemicals at close to reservoir conditions, which in turn requires extensive laboratory tests and evaluations. This work demonstrates the utilization of a microfluidic reservoir analogue for rapid evaluation and screening of commercial surfactants (i.

-selective, Reductive Heck Derived Polynorbornenes with Enhanced Molecular Weights, Yields, and Hydrocarbon Gas Transport Properties.

Next-generation membranes use highly engineered polymeric structures with enhanced chain rigidity, yet difficulties in polymerization often limit molecular weights required for film formation. Addition-type polynorbornenes are promising materials for industrial gas separations, but suffer from these limitations owing to monomeric mixtures that restrict polymerization sites. In this work, a synthetic approach employing the reductive Mizoroki-Heck reaction resulted in -selective products that polymerized up to >99% yields for ROMP and addition-type polymers, achieving molecular weights an order of magnitude higher than addition-type polymers from mixtures and impressive side group stereoregularity.

Interaction of Stabilized Alkylbenzene Sulfonate Surfactants on the Nanoscale with Water-Wet and Oil-Wet Carbonate Surfaces under High-Salinity and High-Temperature Conditions: A QCM-D Study.

Understanding the interactions of surfactants and wettability alteration of surfaces is important for many fields, including oil and gas recovery. This work utilizes the quartz crystal microbalance with dissipation to study the interaction of stabilized linear and branched alkylbenzene sulfonates (ABSs), among the most cost-efficient industrial surfactants, with water- and oil-wet calcite surfaces under high-salinity and high-temperature conditions. Confocal laser scanning microscopy is also used to study the effect of the type of ABS on their interaction with oil-wet calcite surfaces.

Brine-Soluble Zwitterionic Copolymers with Tunable Adsorption on Rocks.

Injection of aqueous fluids into reservoirs as an enhanced oil recovery (EOR) tool has been of great interest in petroleum engineering. EOR using viscous polymer solutions improves the volumetric sweep efficiency. However, significant polymer adsorption on reservoir rock surfaces is one of the greatest challenges in polymer-flooding EOR.

Toward Reservoir-on-a-Chip: Rapid Performance Evaluation of Enhanced Oil Recovery Surfactants for Carbonate Reservoirs Using a Calcite-Coated Micromodel.

Enhanced oil recovery (EOR) plays a significant role in improving oil production. Tertiary EOR, including surfactant flooding, can potentially mobilize residual oil after water flooding. Prior to the field deployment, the surfactant performance must be evaluated using site-specific crude oil at reservoir conditions.

Continuous Multistage Synthesis and Functionalization of Sub-100 nm Silica Nanoparticles in 3D-Printed Continuous Stirred-Tank Reactor Cascades.

The controlled and continuous production of nanoparticles (NPs) with functionalized surfaces remains a technological challenge. We present a multistage synthetic platform, consisting of 3D-printed miniature continuous stirred-tank reactor (CSTR) cascades, for the continuous synthesis and functionalization of SiO NPs. The use of the CSTR platform provides ideal and rapid mixing of precursor solutions, precise injection of additional reagents for multistep reactions, and facile operation when using viscous solutions and handling of syntheses with longer reaction times.

Molecular Assembly of Surfactant Mixtures in Oil-Swollen Micelles: Implications for High Salinity Colloidal Stability.

Alkylbenzene sulfonates are one of the most important synthetic surfactant families, considering their wide applicability, cost-effectiveness, and overall consumption levels. Nevertheless, their low salt tolerance (especially divalent ion contents) prevented their wider applications such as enhanced oil recovery in high salinity reservoirs. Here, using experiments and atomistic molecular dynamics simulations, we demonstrated that the high salinity colloidal stability of alkylbenzene sulfonates can be dramatically increased by mixing with zwitterionic cosurfactants in oil-swollen micelles.

Predicting Stability Constants for Terbium(III) Complexes with Dipicolinic Acid and 4-Substituted Dipicolinic Acid Analogues using Density Functional Theory.

The relative stability constants of Tb(III) complexes exhibiting binding to a series of 4-substituted analogues of dipicolinic acid (2,6-pyridinedicarboxylic acid) (DPA) were calculated using density functional theory (DFT) with the standard thermodynamic cycle. DFT calculations showed that the strengths of the stability constants were modified by the substituents in the following (decreasing) order: -NH > -OH ∼ -CHOH > -imidazole ∼ -Cl ∼ -Br ∼ -H > -F > -I, with the differences among them falling within one to two log units except for -NH. Through population and structural analysis, we observed that the -NH, -OH, -CHOH, and halide substituents can donate electrons via resonance effect to the pyridine ring of DPA while inductively withdrawing electrons with different strengths, thus resulting in the different binding strengths of the 4-substituted DPAs to the Tb(III) ions.

Competition-Based Universal Photonic Crystal Biosensors by Using Antibody-Antigen Interaction.

Sensors capable of detecting different types of biomolecules have widespread applications in the field of biomedical research, but despite many years of research, the development of biosensors suitable for point-of-care (POC) applications in resource-limited areas is still extremely challenging. Sensors based on photonic crystal hydrogels (PCHs) hold much promise in this regard because of their numerous advantages over other existing bioanalytical methods. All current PCH biosensors are however restricted in the types of analytes they can detect sensitively with good selectivity.

Two-dimensional (2D) MnInSe nanosheets with porous structure: a novel photocatalyst for water splitting without sacrificial agents.

Novel 2D porous MnInSe nanosheet photocatalysts have been synthesized for the first time via a simple hydrothermal method, which exhibit promising activity for photocatalytic water splitting without any sacrificial agent due to their large specific surface area, 2D layered morphology, porous structure and suitable energy gap.

Tuning the Potential Energy Landscape to Suppress Ostwald Ripening in Surface-Supported Catalyst Systems.

Rational control of nanoparticle (NP) size distribution during operation is crucial to improve catalytic performance and noble metal sustainability. Herein, we explore the Ostwald ripening (OR) of metal atoms on zeolite surfaces by a coupled theoretical-experimental approach. Zeolites with the same structure (ZSM-5) but different concentrations of aluminum doped into the matrix were observed to yield systematic differences in supported nanoparticle size distributions.

Adsorptive Nature of Surface Barriers in MFI Nanocrystals.

Zeolite nanocrystals with characteristic diffusion lengths of nanometers are widely used in molecular applications to overcome diffusion limitations. However, with a large fraction of external surface area, mass transport in these materials is often limited by the presence of a surface barrier, which limits their overall potential in catalytic or separation applications. Herein, silicalite-1 crystals of varying sizes were synthesized, and the adsorption and diffusion characteristics of four molecules (ethylcyclohexane, methylcyclohexane, cyclohexane, and -1,4-dimethylcyclohexane) were measured to mechanistically evaluate the mass transfer surface barrier.

Organotemplate-Free β Zeolites: From Zeolite Synthesis to Hierarchical Structure Creation.

Interest in the production of β zeolites in the absence of organic structure-directing agent (OSDA) has continued to grow consistently during the past decade. During this time, numerous strategies have been proposed to manipulate the hierarchy of zeolite pore structures in order to facilitate the transport of bulky reactants and to improve the accessibility of active sites in zeolite catalysts. In this work, we describe an organotemplate-free route to produce hierarchical β zeolites.

Vertical 1T/2H-WS nanoflakes grown on 2D-CN: Multiple charge transfer channels designed for enhanced photocatalytic activity.

Two-dimensional (2D) sulfides have attracted much attention as a promising photocatalyst for the hydrogen evolution reaction. In this work, a highly active and stable vertical 1T/2H-WS nanoflakes grown on 2D-CN with multiple charge transfer channels through a simple and efficient colloidal strategy is reported. This three-dimensional (3D) composite presents the usual semiconducting 2H phase WS as well as the unusual distorted octahedral 1T phase WS, which vertically connect 2D-CN constructing an interesting 3D structure with more active sites.

Understanding Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids by Insights from Molecular Dynamics Simulations.

Interest in nanomaterials for subsurface applications has grown markedly due to their successful application in a variety of disciplines, such as biotechnology and medicine. Nevertheless, nanotechnology application in the petroleum industry presents greater challenges to implementation because of the harsh conditions (i.e.