Current Opinion in Colloid & Interface Science最新文献

Amphiphilic lipids are essential biomolecules, critical components in nature's functional materials, and crucial nutrients in food. Being sustainable, biocompatible, and biodegradable with versatile structural properties, they have great potential as functional building blocks for innovative food materials. They can tailor factors including texture, mouthfeel, appearance, and nutrient delivery. Their structural analysis from the angstrom to the micrometer range lies at the core of the functional material design and is fundamental for their further biological understanding.

We discuss recent advances in colloidal structure formation and challenges in characterizing structures and dynamics in lipid-based materials on the microstructural level. We provide examples of how lipid self-assemblies, particularly lyotropic liquid crystalline structures, can enhance food materials. The interdisciplinary development of this growing research field helps explore new functionalities for food applications.

Surfactants play an increasingly important role across diverse scientific and industrial domains. Gaining a deeper understanding of their molecular behavior at various interfaces is thus becoming ever more essential. Despite considerable advances in experimental techniques, challenges in capturing the detailed molecular-level behavior of surfactants at interfaces persist. In this work, we discuss the potential of combining various experimental methods with atomistic molecular dynamics (MD) simulations in studies of surfactant interfacial layers. MD simulations have emerged as a powerful tool that provides detailed insights into molecular structures and dynamic properties, some of which are inaccessible through experimental means alone. By re-examining existing MD simulation data and directly comparing them with experiments, we illustrate how MD simulations can be used to validate and support thermodynamic models and interpret spectroscopy and scattering data. While combining scattering experiments on Langmuir layers of insoluble surfactants with simulations seems to be well-established by now, we emphasize the growing capability of scattering techniques to also investigate the more disordered Gibbs layers of soluble surfactants. Here, MD simulations can now connect the pressure and adsorption isotherms with the equation of state. In light of the ongoing parallel developments of computational and experimental methods, their synergistic use can be expected to drive future progress in surfactant research.

In this paper, I delve into the physics of foams within the context of Enhanced Oil Recovery (EOR). Foams present a promising prospect for use in EOR, applicable to both conventional and non-conventional oil wells. A primary challenge faced by oil industry technologists is ensuring foam stability in porous media under harsh conditions of temperature, pressure, and salinity. To surmount these challenges, a profound understanding of the physicochemical mechanisms governing foam formation and stability at a microscopic level is required. In this article, I explore some fundamental aspects of foam physics that should be considered when developing foam systems for EOR. I conclude the paper by briefly discussing the use of machine learning in the design of foam-assisted EOR, and by highlighting the potential of smart foams in the oil industry.

Solid particles have been well known to stabilize foams/bubbles by adsorption at gas–liquid interfaces. Synthetic polymer particles are a particularly attractive stabilizer for the foams/bubbles, because their sizes, shapes, surface/bulk chemistries, hydrophilicity-hydrophobicity balance and softness can be tailored and modified by heterogeneous polymerization techniques, (co)polymerizations of functional monomers, polymer reactions and polymer processing. Additionally, a wide range of stimulus-responsive characteristics and film-forming nature of the polymer particles could inspire the design of functional and well-defined particle-stabilized foams/bubbles and materials based on them. This short review overviews aqueous foams/bubbles stabilized solely with synthetic polymer particles and material chemistry based on them, followed by discussions on research directions for the future.

Trisiloxane surfactants have been reported to have unusual interfacial properties, which was considered to be the root cause why some trisiloxane surfactants show exceptionally good spreading properties on hydrophobic substrates, so-called superspreading. Therefore, the behavior of those surfactants at all interfaces involved has been critically discussed, because some of the findings published in the past are quite counterintuitive. As it turns out, there does not seem to be anything unusual concerning trisiloxane surfactants – their interfacial behavior follows the rules of basic physical chemistry.

Biosurfactants (BSs) have been extensively researched due to their potential applications in various fields, including textiles, cosmetics, pharmaceuticals, agriculture, and oil remediation. These BSs possess a diverse range of physical, chemical, and biological properties. In recent years, researchers have combined these biosurfactants with both natural and synthetic polymers, resulting in the development of advanced material systems that exhibit a unique combination of properties. This review focuses on highlighting the recent advancements in these biosurfactant-polymer material systems and identifies existing gaps in the literature. The combination of biosurfactants with polymers has led to the formation of interpenetrated hydrogels, films, chemically modified surfaces, vesicles, functionalized nanofiber non-woven mats, nano-formulations, and nano-assemblies. Some studies have also investigated the interactions between biosurfactants and polymer molecules. In most cases, non-specific, non-covalent interactions, such as electrostatic interactions, hydrogen bonding, and hydrophobic interactions have been found to govern the properties of these systems. Moreover, promising results have been achieved through the covalent modification of polymer surfaces, followed by functionalization using biosurfactant molecules. The literature demonstrates that these advanced materials could find applications in various fields, including drug delivery, bioremediation, biomedical materials, and as antimicrobial agents. These findings indicate the promising potential of biosurfactant-polymer systems for future advancements in these areas.

Biosurfactants offer significant advantages over their chemical counterparts due to their environmentally friendly nature. Among them, glycolipids are one of the most studied classes and possess the ability to self-assemble into various structures. The ability of glycolipid bioamphiphiles to impart viscoelasticity and immobilize the solvent underscores their potential use beyond their surface-active properties, positioning them as efficient low-molecular-weight gelators for the development of functional soft materials. Herein, we review the viscoelastic properties of self-assembled glycolipid systems, namely worm-like micelles, fibrillar, and lamellar hydrogels. Next, recent trends in the development of multicomponent systems from the orthogonal self-assembly of glycolipids and biopolymer gels are highlighted.

Over the last two decades, a significant body of research has been developed trying to understand the association and properties of mixtures formed by oppositely charged polyelectrolytes and surfactants. Particular emphasis has been given to their interfacial properties and the intriguing formation of nonequilibrium states. The synergy between these components at interfaces has attracted considerable attention due to its relevance in various industrial and biological applications. The combination of oppositely charged entities leads to complex interactions that influence the stability and behavior of interfaces. This review critically examines recent advances toward understanding the interfacial behavior when polyelectrolytes and surfactants coexist. Emphasis is placed on the existence of nonequilibrium states, shedding light on transient phenomena and kinetic aspects that play a crucial role in the overall system behavior. This will provide insights into the mechanisms governing the interfacial phenomena in these mixed systems. In summary, this review will contribute to the fundamental understanding of colloidal and interfacial science, offering a valuable perspective on designing and optimizing materials with tailored properties.

Sun protection formulations have undergone significant advancements, incorporating soft nanostructures to enhance their efficacy, safety, and aesthetic appeal. Nanoemulsions, with their controlled droplet size and improved ultraviolet (UV) absorption, are utilized in sunscreen formulations, boosting their photoprotective effects. Microemulsions, offering enhanced dispersion and delivery, enable the incorporation of new active ingredients, improving stability and skin permeation. Pickering emulsions, stabilized by particles provide stable, eco-friendly alternatives. Nanostructured lipid carriers, facilitate efficient encapsulation and delivery of various compounds, enhancing both UV protection and skin penetration. Nanoparticles (NPs), demonstrate promising results in improving photostability, preventing skin penetration, and enhancing antioxidant properties of sunscreens. SunSpheresTM, advanced UV boosters, scatter UV radiation effectively when integrated into sunscreen formulations, significantly increasing their sun protection factor values. This review highlights the diverse applications of soft nanostructures in sun protection, emphasizing their crucial role in the evolution of sunscreens for optimal skin safety and protection against UV radiation.