Current Opinion in Colloid & Interface Science最新文献

Dynamic dilational viscoelasticity is an important physical characteristic of interfacial layers because it influences the dynamics and stability of multiphase systems, such as thin liquid films, foams and emulsions. Dilational viscoelasticity depends on many factors. Less studied, but very important, factors are the solubility of the solution components in two contacting liquids, the simultaneous presence of two solution components within a mixed adsorption layer and the curvature of the interface. In this review, we considered several new developments of previously proposed models, which can be used for the analysis of new experimental data. In the presence of such effects, the behaviour of the dilational viscoelasticity becomes more complicated and requires more parameters for its description. An alternative way is to use phenomenological models, which do not identify the particular relaxation processes but propose a description of the dilational viscoelasticity in general terms.

Perovskite solar cells (PSCs) have rapidly advanced as a promising new photovoltaic generation technology. In a decade, a remarkable power conversion efficiency of 26% was achieved, comparable to silicon-based traditional solar cells. However, their stability and sustainability still need to be improved before commercialization. The potential replacement of some of the inorganic components in the PSCs with organic ones could address these concerns as the organic components may offer the advantages of being biodegradable, low cost, and easily processed, with the potential of protecting the perovskite from the ambient environment. Thus, this review focuses on the recent developments in organic electron transport materials (ETMs) and hole transport materials (HTMs). Additionally, machine-learning insights and perspectives for future research directions are proposed for the advancements of PSCs.

Liquid foams, as colloidal systems comprising a dispersed gas phase within a continuous liquid medium, exhibit unique structural and rheological properties beneficial for various industrial and environmental applications. This review synthesizes current knowledge on the fundamentals, stability mechanisms, and practical applications of liquid foams. We first discuss foam structures, transitioning from ball to wet and dry foams, influenced by the liquid fraction and surfactant presence, which also influence the foam’s mechanical and stability properties. We further describe the mechanisms of foam generation (for confined foams), stability, and decay, highlighting the roles of snap-off, lamellae division, and leave-behind in foam formation and the adverse effects of coarsening, gravity drainage, and collapse on foam stability. Additionally, the review covers the rheological behavior of foams under shear stress, illustrating their complex viscoelastic or viscoplastic nature. Finally, we review recent studies of foam injection and displacement in porous structures, utilizing Hele–Shaw cells and microfluidics.

Profile analysis tensiometry (PAT) with drops and bubbles is a successful methodology to characterize liquid–fluid interfaces. Questions about the most suitable size of drops and bubbles have been solved now on the basis of dimensionless numbers. The consideration of the standard deviation between measured and calculated liquid profiles as a sensitive measure for the applicability of PAT provides a tool for its correct use. For solutions of highly surface-active compounds, bulk depletion effects can cause systematic errors in the analysis of adsorption kinetics, equations of state, and the visco-elastic interfacial behavior of liquid adsorption layers. Great progress has been made in measurements of interfacial dilational rheology with large amplitude perturbations providing additional information about structure and dynamics of complex adsorption layers. Also, first attempts are successfully made to use artificial intelligence (AI) to enhance the efficiency of PAT applications. Thus, PAT has established a solid position in surface science.

The applications of artificial intelligence (AI) and machine learning (ML) approaches are rising in formula optimization, ingredient selection, performance prediction, and structure-properties analysis in formulated product development for the cosmetic industry. The present review aims to give a critical discussion regarding how AI and ML assist in the development of key component materials used in cosmetics and formulated products including surfactants, polymers, fragrances, preservatives, and hydrogels. Hydrogels are reviewed here as a promising candidate to open a new frontier for the future cosmetics and personal care product industry, due to their excellent biocompatibility, excellent drug-delivering ability, and high water content. We also discuss the use of ML for formula optimization and hazardous ingredient detection such as sensitizing and allergic components. All the research publications reviewed in the present work are accomplished in the past 4 years to reflect the current research trends and progress in ML-assisted advancement in cosmetics and personal care product development.

The phase equilibrium shift caused by changes in polymer-liquid compatibility under the influence of external or internal factors is discussed as the main mechanism of gel formation. Wherein, it is assumed that the gel is a solid, non-flowing soft substance formed due to incomplete phase decomposition of a solution. The sol-gel transition occurs through the intermediate stage of the formation of a viscoelastic yielding medium. The liquid-yielding medium-gel transition results in fundamental changes in the rheological properties of the substance. Therefore, the study of the kinetics of the evolution of rheological properties at various stages of gelation is an important tool for understanding this phenomenon. The review contains a discussion of recent publications and the formulation of some challenging problems.

Foamed cereal foods are a significant part of our daily diet. Colloidal and interfacial science principles provide insights on how to devise novel aerated cereal foods that may also address environmental and human health needs in our diets and for optimizing the sensory and nutritional quality of foamed cereal products. We review recent literature where colloidal science principles have been employed to understand relations between the creation of bubbles in food materials, bubble growth and interactions, and how this history governs the microstructure and the mechanical properties of foamed cereal products that are critical to the appearance and quality of a range of food products such as bread, cakes, snack foods, and breakfast cereals. Product density and its frequently measured corresponding quality equivalent, specific volume, are key considerations of both the visual appeal and the eating quality of foamed cereal products.

Chiral surfactants represent a class of amphiphilic compounds characterized by hydrophilic headgroups and hydrophobic tails, coupled with one or several chiral centers within their molecular structures. Beyond possessing typical surfactant properties, they exhibit inherent asymmetry. Their aggregation behaviors and self-assembled structures can be effectively modulated by substituting chiral groups or introducing functional groups at the chiral center. Numerous endeavors have been undertaken to craft chiral surfactants with sophisticated physicochemical properties and burgeoning applications. This review delves into the aggregation behaviors of chiral surfactants sourced from various origins and possessing different molecular structures, with a focus on key parameters including headgroup, spacer and counterion. Moreover, applications of these multifunctional chiral surfactants are summarized across several active domains, including chiral recognition, enantiomer separation, asymmetric catalysis and the synthesis of chiral nanomaterials. Finally, it outlines perspectives and future challenges associated with chiral surfactants, highlighting avenues for further exploration and advancement in this field.