Preparation of amphiphilic Janus SiO2 particles and its application on polyacrylate emulsion

Preparation of asymmetric Janus hollow silica microparticle and its application on oily wastewaters

Janus nanoparticles have aroused the interest of scholars because of their highly efficient emulsification of spilled oils in wastewater. In this work, interfacially active Janus hollow glass microparticles (J-HGMPs) of asymmetric wettability were designed and synthesized in order to achieve more efficient separation of emulsified oil droplets from oily wastewater. Surface characteristic techniques such as FTIR, SEM, zeta potential and contact angle measurements had been employed to assess the amphiphilic surface properties of J-HGMPs. The oil removal/recovery performance of J-HGMPs in different oil-water systems and their interfacial activities were studied. As a particulate emulsifier, J-HGMPs could remove/recover > 96% oil from oil-water mixed phase. The results showed that J-HGMPs had strong interfacial activities and anchored firmly at oil/water interfaces. This high adsorption energy was also evaluated and verified via the calculation of Gibbs free energy. Overall, this study provided a novel and low-cost oil recovery method via a convenient buoyancy force that could be effectively applied in the treatment of oil spills while achieving the goal of benign and green environmental protection.

Comparison of Oxidative and Physical Stabilities of Conjugated Linoleic Acid Emulsions Stabilized by Glycosylated Whey Protein Hydrolysates via Two Pathways

The objective of the research was to analyze and compare the oxidative and physical stabilities of conjugated linoleic acid (CLA) emulsions stabilized by two glycosylated hydrolysates (GPP-A and GPP-B) that were formed via two different pathways. This study showed that GPP-A exhibited higher browning intensity and DPPH radical scavenging ability in comparison with GPP-B. Moreover, the CLA emulsion formed by GPP-A exhibited a lower creaming index, average particle size, primary and secondary oxidative products, in comparison with GPP-B-loaded emulsion. However, the GPP-A-loaded emulsion showed a higher absolute potential and fraction of interfacial adsorption than that of the CLA emulsion formed by GPP-B. Therefore, the CLA emulsion formed by GPP-A exhibited stronger stabilities in comparison with the GPP-B-loaded emulsion. These results suggested that GPP-A showed an emulsification-based delivery system for embedding CLA to avoid the loss of biological activities. Additionally, the development of CLA emulsions could exert its physiological functions and prevent its oxidation.

Shedding Light on Luminescent Janus Nanoparticles: From Synthesis to Photoluminescence and Applications

Luminescent Janus nanoparticles refer to a special category of Janus-based nanomaterials that not only exhibit dual-asymmetric surface nature but also attractive optical properties. The introduction of luminescence has endowed conventional Janus nanoparticles with many alluring light-responsive functionalities and broadens their applications in imaging, sensing, nanomotors, photo-based therapy, etc. The past few decades have witnessed significant achievements in this field. This review first summarizes well-established strategies to design and prepare luminescent Janus nanoparticles and then discusses optical properties of luminescent Janus nanoparticles based on downconversion and upconversion photoluminescence mechanisms. Various emerging applications of luminescent Janus nanoparticles are also introduced. Finally, opportunities and future challenges are highlighted with respect to the development of next-generation luminescent Janus nanoparticles with diverse applications.

The advantages of nanoparticle surfactants over Janus nanoparticles on structuring liquids

The nanoparticle (NP) surfactants generated in situ by binding NPs and polymers can assemble into an elastic NP monolayer at the interface of two immiscible liquids, structuring the liquids. Janus NPs can be more strongly bound to the interface than the NP surfactants, but they are unable to structure liquids into complex shapes due to the difficulty of assembling the jamming arrays. By molecular dynamics simulations, we give an insight into the better performance of NP surfactants than Janus NPs on dynamically structuring liquids. The high energy binding of Janus NPs to the interface will drive the Janus NPs to assemble into micelles in binary liquids. The micelles are stabilized in one liquid by encapsulating a little of the other liquid, hindering interfacial adsorption when the interface is marginally extended upon liquid deformation. In contrast, the in situ formed NP surfactants can rapidly fill the enlarged interfacial area to arrest the consecutive shape changes of the liquids. Moreover, NP surfactants can be designed with an appropriate coverage ratio (≤50%) of NP surface bearing host-guest sites to avoid dissolution and impart a desirable mechanical elasticity to their assembly.

Preparation of Water-dispersible Janus Nanosheets from K4Nb6O17·3H2O and Their Behaviour as a Two-dimensional Surfactant on Air-Water and Water-Toluene Interfaces

K4Nb6O17·3H2O-based Janus nanosheets with water dispersibility and surface activity were prepared via sequential regioselective surface modification. To provide individual Janus nanosheets with these two properties, phenylphosphonic acid and phosphoric acid...

Preparation of an amphiphilic Janus SiO2/fluorinated polyacrylate latex film and its application as a hydrophobic fabric agent

Amphiphilic Janus particles are characterized by their anisotropic morphology and unique physical and chemical properties. In the present research, amphiphilic Janus particles were used as stabilizing agents to prepare a fluorine-containing polyacrylate composite emulsion. The influences of the structure and dosage of amphiphilic Janus SiO₂ particles and the amount of fluorine-containing monomer hexafluorobutyl methacrylate on the stability of the composite emulsion were investigated. It was noticed that when the hydrophilic and hydrophobic groups of Janus SiO₂ particles were polyacrylamide and polymethyl methacrylate, respectively, the stabilization of the polyacrylate emulsion with Janus SiO₂ particles was achieved. When 0.3 wt% of polyacrylamide/polymethyl methacrylate amphiphilic Janus SiO₂ particles and 8 wt% of hexafluorobutyl methacrylate were used, a stable composite emulsion was obtained. The conversion rate reached 98.7% with an average particle size of 500 nm. The composite emulsion was applied for fabric finishing. The water contact angle of the fabric increased from 21.4° to 140.2°, demonstrating its greatly improved hydrophobicity. Therefore, it could be inferred that the synergistic effect of amphiphilic Janus SiO₂ nanoparticles and hexafluorobutyl methacrylate improved the water resistance of the latex film.