Lei Xie’s research while affiliated with South Central College and other places

Flexible films with optimal piezoelectric performance and water‐triggered dissolution behavior are fabricated using the co‐dissolution–evaporation method by mixing trimethylchloromethyl ammonium chloride (TMCM‐Cl), CdCl2, and polyethylene oxide (PEO, a water‐soluble polymer). The resultant TMCM trichlorocadmium (TMCM‐CdCl3) crystal/PEO film exhibited the highest piezoelectric coefficient (d33) compared to the films employing other polymers because PEO lacks electrophilic or nucleophilic side‐chain groups and therefore exhibits relatively weaker and fewer bonding interactions with the crystal components. Furthermore, upon slightly increasing the amount of one precursor of TMCM‐CdCl3 during co‐dissolution, this component gained an advantage in the competition against PEO for bonding with the other precursor. This in turn improved the co‐crystallization yield of TMCM‐CdCl3 and further enhanced d33 to ≈71 pC/N, exceeding that of polyvinylidene fluoride (a commercial flexible piezoelectric) and most other molecular ferroelectric crystal‐based flexible films. This study presents an important innovation and progress in the methodology and theory for maintaining a high piezoelectric performance during the preparation of flexible multi‐component piezoelectric crystal films.

In recent years, the demand for lithium (Li) has been on the rise as Li-ion batteries are playing an increasingly important role in powering the global transition to a low-carbon society. In contrast to the predominant production of lithium from hard rock, lithium extraction from brine sources has proven more economical and sustainable. However, substantial challenges remain, including the low efficiency of the extraction process, especially for brines of high salinity, complex composition and poor selectivity against magnesium, the major competing species. Here we show a loose nanofiltration process involving ethylenediaminetetraacetic acid (EDTA) for direct and efficient Li⁺ extraction as well as effective Mg²⁺ utilization from salt-lake brines. Taking advantage of selective binding between EDTA⁴⁻ and Mg²⁺, our process achieves ultrahigh Mg²⁺ rejection of 99.85%, ultrafast Li⁺ flux of ~4.34 mol m⁻² h⁻¹ and unprecedented Li⁺/Mg²⁺ separation factor (~679) under industrial conditions (127.06 g l⁻¹). More importantly, the Li⁺ recovery rate reaches 89.90% through a two-stage filtration process, while Mg²⁺ waste is converted to nanostructured Mg(OH)2 and 98.87% of EDTA⁴⁻ can be regenerated. Our scalable process minimizes environmental impact while maximizing resource utilization, thereby catalysing the shift toward a more sustainable future.

Lubricant‐infused slippery surfaces have recently emerged as promising antifouling coatings, showing potential against proteins, cells, and marine mussels. However, a comprehensive understanding of the molecular binding behaviors and interaction strength of foulants to these surfaces is lacking. In this work, mussel‐inspired chemistry based on catechol‐containing chemicals including 3,4‐dihydroxyphenylalanine (DOPA) and polydopamine (PDA) is employed to investigate the antifouling performance and repellence mechanisms of fluorinated‐based slippery surface, and the correlated interaction mechanisms are probed using atomic force microscopy (AFM). Intermolecular force measurements and deposition experiments between PDA and the surface reveal the ability of lubricant film to inhibit the contact of PDA particles with the substrate. Moreover, the binding mechanisms and bond dissociation energy between a single DOPA moiety and the lubricant‐infused slippery surface are quantitatively investigated employing single‐molecule force spectroscopy based on AFM (SM‐AFM), which reveal that the infused lubricant layer can remarkably influence the dissociation forces and weaken the binding strength between DOPA and underneath per‐fluorinated monolayer surface. This work provides new nanomechanical insights into the fundamental antifouling mechanisms of the lubricant‐infused slippery surfaces against mussel‐derived adhesive chemicals, with important implications for the design of lubricant‐infused materials and other novel antifouling platforms for various bioengineering and engineering applications.

A R T I C L E I N F O Keywords: bitumen oil sands bitumen flotation bubbles surface interactions A B S T R A C T The surface interactions of air bubbles and other components (e.g., particles, oil droplets) significantly influence the operation efficiency of a variety of engineering processes such as oily water treatment, bitumen extraction and flotation. Herein, the surface interactions of air bubbles with two types of Athabasca bitumen samples in aqueous solutions of varying pH, salinity, type of cations and in the presence of surfactants have been systematically characterized using a bubble probe atomic force microscope (AFM) technique. AFM imaging has revealed that exposure to high concentrations of NaCl and CaCl 2 solutions or alkaline environments causes roughening of the bitumen surfaces. The results of surface force measurements demonstrate that the interaction and attachment behaviors between bubbles and bitumen are significantly affected by ionic strength, solution pH, and the presence of surfactants. The experimental force measurement results could be accurately described by a theoretical model that incorporates Reynolds lubrication theory and augmented Young-Laplace equation, with the inclusion of disjoining pressure. In low-salinity conditions, the bubble-bitumen interaction is dominated by electric double layer (EDL) repulsion, which prevents surface attachment. This effect is more pronounced at elevated pH conditions. In high-salinity solutions, however, the EDL interactions are significantly reduced, and the hydrophobic interaction becomes the dominant factor, overcoming the van der Waals repulsion and leading to the attachment of bubbles to bitumen surfaces. Raising aqueous pH weakens the bubble-bitumen hydrophobic interaction, whereas the introduction of calcium ions strengthens this interaction, resulting in enhanced surface attachment. Interestingly, even in high-salinity conditions, the presence of a small number of surfactants can inhibit bubble-bitumen contact, mainly caused by reduced hydrophobic attraction and increased steric repulsion. This work provides valuable nanoscale insights into how bubbles and bitumen interact in intricate aqueous environments, and the results show practical implications for controlling similar interfacial phenomena in various engineering processes.