Natural Rice Starch Granules for Green Cleaning

Fast Interfacial Polymerization for Stabilizing Emulsion Droplets with Polymer Films beyond Emulsifiers

Stabilizing emulsion droplets with amphiphilic emulsifiers are the current prevailing method, but the extensive use of such amphiphilic substances has caused widespread concerns. In this Perspective, three traditional methods for the stabilization of emulsion droplets according to the type of emulsifiers used are outlined, and the emphasis is placed on the mechanism of steric hindrance for emulsion stabilization. Then, we provide a concise introduction and discussion of the fast interfacial polymerization method as a new strategy for preparing stable emulsifier-free emulsion droplets with a polymer film, including its research background, current progress, and possible development directions. It is anticipated that this paper will promote the development of emulsifier-free emulsion production via fast interfacial polymerization and other related methods.

Self-Shaping Microemulsion Gels for Cultural Relic Cleaning

Cleaning is a foundational and essential operation of protection and restoration of cultural relics, which is also the key step of follow-up works. To overcome the problems of uncontrollable diffusion of cleaning solvents and poor coverage of the cleaning solvent carriers on rough surfaces, here, we propose a strategy of using a self-shaping microemulsion gel that is prepared via emulsifying oleophilic solvents into the specific shear-thinning hydrogel structures. The gel can adaptively cover rough surfaces during the cleaning process coupled with avoidance of unnecessary diffusion of the cleaning solvents, and the mechanical reinforcement of in situ polymerized double-network gels enables its easy peeling off from the surfaces without leaving determinable residues. As a representative demonstration, Paraloid B72, a widely used material for the repair and reinforcement of cultural relics, is employed as a model discolored coating, which can be effectively removed from the rough surface of simulated cultural relics after treatment with the resulting gels. Convincingly, the strategy of constructing agarose/polyacrylamide hybrid double-network gels with shear-thinning and self-shaping performances for the cleaning of cultural relics not only improves the convenience and accuracy of operation but also exhibits an efficient cleaning effect, which will greatly expand the application of microemulsion gels in the cleaning of rough surfaces of cultural relics.

Effect of pH or Metal Ions on the Oil/Water Interfacial Behavior of Humic Acid Based Surfactant

Humic acid, a kind of widespread organic macromolecule on earth, is naturally formed through the microbial biodegradation of plant, animal, and microorganism residues. Because of the large number of active functional groups (phenolic hydroxyl and carboxyl), humic acid has been considered as a biocompatible, green, and low-cost biosurfactant recently. In this work, based on the sensitivity of humic acid to the external chemical environment, the oil/water interfacial behavior of sodium humate at different pH or in the presence of metal ions is closely investigated. Sodium humate is significantly enriched toward the oil/water interface at either low pH or high metal-ion concentration to adjust the properties of the prepared emulsion, but the mechanisms are proved to be different when considering the influence of pH and metal ions. Besides, to the best of our knowledge, humic acid based surfactant is proposed as a Pickering emulsifier for the first time, known as solid surfactant. This work promises the great potential of humic acid as a natural environment-responsive surfactant and has important implications for the application of humic acid based surfactant in industry and understanding of the role of humic acid in the natural environment.

Three Birds with One Stone: Injectable CaC2 Nanobombs with Triple Effects for Minimally Invasive Tumor Chemical Ablation

Percutaneous chemical ablation (PCA) is the oldest and most established technique for treating small solid tumors in organs. It has been widely used in clinics even on an outpatient basis. However, compared with the emerging microwave or magnetic hyperthermal ablation, PCA is faced with relatively poor necrosis results and needs to repeat multiple sessions. Inspired by the three effects in the bomb's explosive process, we herein expect to combine calcium carbide (CaC₂) nanoparticles into the PCA technique to generate local explosion within tumor tissues, leading to three killing effects against tumors to further improve the ablation efficacy of PCA. Through an efficient wet milling procedure with poly(ethylene glycol), three kinds of nanobombs including CaC₂, calcium oxide (CaO), and calcium hydroxide (Ca(OH)₂) were fabricated, and they all exhibited desirable suspension stability. Among these nanobombs, in particular CaC₂ nanobombs showed a synergistic effect that the generation of ethyne gas bubbles could facilitate the most rapid diffusion of hyperthermia. Also, CaC₂ nanobombs offered the powerful ability to cause the sudden rise of local high temperature and pH value. According to the in vivo mice tumor excision trial, the tumors of 75% of cases that received CaC₂ treatment were destroyed and eradicated, exhibiting the excellent ablation ability of CaC₂ nanobombs against small solid tumors planted in mice.