Current Opinion in Colloid & Interface Science最新文献

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.

Microbial biosurfactants are an attractive and promising class of molecules with the potential to replace oil-derived surfactants for the formulation of ecofriendly and biocompatible products. In this review, we discuss literature findings, mostly reported in the last decade, on the self-assembly of the four main classes of microbial biosurfactants, i.e., rhamnolipids, mannosylerythritol lipids, sophorolipids, and surfactin. All of them present composite molecular structures, characterized by different functional groups and ionisable moieties, and a high conformational flexibility. Where possible, we discuss the formation of different aggregate morphologies in terms of biosurfactant molecular structure and variation of environmental parameters. We highlight how the biosurfactant self-assembly is regulated by a complex interplay between various intermolecular interactions, including H-bonds and steric constraints, besides electrostatic and hydrophobic interactions. For this reason, we show that common theoretical approaches to amphiphile self-assembly, such as the critical packing parameter, have limitations in rationalizing and predicting biosurfactant aggregation behaviour.

The increasing trend towards low Greenhouse gas emissions, sustainable sourcing and waste minimisation has led to a large number of new surface-active species being made available whose unique sourcing and physical properties render them important aids towards achieving nett zero carbon in Home and Personal Care formulations. The X-ray and neutron small angle scattering techniques together with cryo-TEM and molecular modelling are important tools for the characterisation of their self-assembled microstructures in aqueous solution. In this Chapter, some of the recent studies of mixtures of a selection of novel biosurfactants, sophorolipids, rhamnolipids and triterpenoid saponins, with other commonplace anionic and nonionic surfactants are presented and discussed.

Glycation, i.e., the covalent reaction between reactive carbonyl groups of sugar with biomolecules such as protein, lipid, or DNA, is integral to many physiological functions, including biolubrication. Although glycation, also commonly termed as “Maillard reaction”, has been used extensively to modify flavors and stabilize food colloids, its applications for achieving desired oral lubrication performance of food are in its infancy. This review discusses glycation as a biolubrication tool to provide stimulus to future designing of food colloids. Specifically, we examine how glycation drives biolubrication of soft tissues with examples of lubricin and mucin as “brush-like”, nature-engineered, high performance, aqueous lubricants. Recent advances in Maillard conjugation to modify tribology, rheology, adsorption, or surface hydrophobicity of dietary proteins are covered. Lastly, we transfer molecular rules from polymer physics to food colloid science to inspire repurposing glycation of dietary proteins to rationally design the next-generation of lubricious alternative protein-based foods that are often delubricating.

It is now well established that the combination of proteins and polysaccharides makes it possible to obtain textures that can be used by the food industry. However, consumer demand for more environmentally friendly and healthier foods is leading to the development of new ingredients (particularly plant proteins) for which the know-how acquired on animal proteins cannot be directly transposed. The aim of this review is to take stock of the work published between 2021 and 2023 on gelation of polysaccharide/protein mixtures on their own or in the presence of oil. The emphasis is on the structural and rheological studies of these (emul)gels. In addition to the composition and variability of the ingredients, there are a multitude of formulation parameters (pH, salt, temperature, etc.) and shaping parameters (pressure, homogenisation, etc.), which makes it difficult to compare the different studies in order to conclude on general structure/properties relationships.