Two-dimensional demixing within multilayered nanoemulsion films.

Benefiting from the demixing of substances in the two-phase region, a smart polymer laminate film system that exhibits direction-controlled phase separation behavior was developed in this study. Here, nanoemulsion films (NEFs) in which liquid nanodrops were uniformly confined in a polymer laminate film through the layer-by-layer deposition of oppositely charged emulsion nanodrops and polyelectrolytes were fabricated. Upon reaching a critical temperature, the NEFs exhibited a micropore-guided demixing phenomenon. A simulation study based on coarse-grained molecular dynamics revealed that the perpendicular diffusion of oil droplets through the micropores generated in the polyelectrolyte layer is crucial for determining the coarsening kinetics and phase separation level, which is consistent with the experimental results. Considering the substantial advantages of this unique and tunable two-dimensional demixing behavior, the viability of using the as-proposed NEF system for providing an efficient route for the development of smart drug delivery patches was demonstrated.

Hydrophobically Modified Cellulose Nanofibers-Enveloped Solid Lipid Microparticles for Improved Antioxidant Cargo Retention.

This study introduces a cellulose nanofiber surfactant system, in which the surface is hydrophobically modified with different alkyl chain structures for the effective envelopment of solid lipid microparticles (SLMs). To endow bacterial cellulose nanofibers (BCNFs) with excellent ability to assemble at the lipid-water interface, alkyl chains with designated molecular structures, such as decane, didecane, and eicosane, are covalently grafted onto the BCNF surface. Interfacial tension and interfacial rheology measurements indicate that dialkyl chain-grafted BCNFs (diC10 BCNF) exhibit strong interfibrillar association at the interface. The formation of a dense and tough fibrillary membrane contributes significantly to the enveloping of the SLMs, regardless of the lipid type. Because the diC10 BCNF-enveloped SLMs exhibit a core molecular crystalline phase at the microscale, they can immobilize an oil-soluble antioxidant while maintaining its long-term storage stability. These findings show that the cellulose-surfactant-based SLM technology is applicable to the stabilization and formulation of readily denatured active ingredients.

Structuring Pickering Emulsion Interfaces with Bilayered Coacervates of Cellulose Nanofibers and Hectorite Nanoplatelets.

In this study, we present a water-in-silicone oil (W/S) Pickering emulsion system stabilized via in situ interfacial coacervation of attractive hectorite nanoplatelets (AHNPs) and bacterial cellulose nanofibrils (BCNFs). A bilayered coacervate is generated at the W/S interface by employing the controlled electrostatic interaction between the positively charged AHNPs and the negatively charged BCNFs. The W/S interface with the bilayered coacervate shows a significant increase in the interfacial modulus by 2 orders of magnitude than that with the AHNPs only. In addition, we observe that water droplets are interconnected by the BCNF bridging across the continuous phase of silicon, which is attributed to the diffusive transport phenomenon. This droplet interconnection results in the effective prevention of drop coalescence, which is confirmed via emulsion sedimentation kinetics. These results indicate that our bilayered coacervation technology has the potential of developing a promising Pickering emulsion platform that can be used in the pharmaceutical and cosmetic industries.

Bacterial cellulose nanofibrils-armored Pickering emulsions with limited influx of metal ions.

This study introduces a hydrophobically modified bacterial cellulose nanofibrils (BCNF)-stabilized Pickering emulsion system, which can limit the influx of metal ions through the interface. We showed that the C18 alkyl chain-grafted BCNF (C18BCNF) can readily associate to generate a resilient thin membrane at the oil-water interface regardless of the type of oil, which is essential for the production of stable emulsion drops. The viscoelasticity of C18BCNF-armored Pickering emulsion was feasibly tunable by manipulating the grafting amount of the C18 alkyl chains, as well as controlling the C18BCNF concentration. We also demonstrated that the C18BCNF membrane formed at the interface effectively entrapped metal ions through electrostatic binding with the carboxyl groups on C18BCNF, thus maintaining original UV-absorbing capability of chemical UV filter-containing emulsions. We expect that the BCNF surfactant fabricated in this study has immense potential for the development of various complex emulsion products.

Highly stable, electrostatically attractive silicone nanoemulsions produced by interfacial assembly of amphiphilic triblock copolymers.

This article presents a useful and promising approach for fabricating extremely stable silicone oil nanoemulsions, whose liquid-liquid interface is structured with a thin film of amphiphilic triblock copolymers. For this, two types of amphiphilic triblock polymer, poly(2-methacryloyloxy ethyl phosphorylcholine)-block-poly(ε-caprolactone)-block-poly(2-methacryloyloxy ethyl phosphorylcholine) (PMPC-PCL-PMPC) and poly(2-aminoethyl methacrylate)-block-poly(ε-caprolactone)-block-poly(2-aminoethyl methacrylate) (PAMA-PCL-PAMA), were synthesized by atom transfer radical polymerization. Employing the phase separation technique was critical for the formation of thin polymer interfaces, of less than 10 nm, thus eventually producing structurally stable silicone oil nanoemulsions. The co-assembly of PAMA-PCL-PAMA with PMPC-PCL-PMPC enabled the patching of positive charges on the surface of the emulsion drops. We show that these charged silicone oil nanoemulsions could be used to form a multilayer emulsion thin film by layer-by-layer deposition. Finally, we experimentally demonstrate that the silicone oil nanoemulsions fabricated in this way were highly stable and had the ability to electrostatically interact with hair, which enabled complete coating of the hair surface with a layer of silicone oil.

Physicochemical and Sensory Properties of Yogurt Supplemented with Corni fructus during Storage.

This study was carried out to determine a possibility of adding Corni fructus extract (CFE) into yogurt for improving the neutraceutical properties of yogurt and the effects of adding CFE (2∼6%, v/v) on the physicochemical and sensory properties of the products during a 15-day storage period at 4°C. Incorporation of CFE into the yogurt samples resulted in a significant pH reduction and a significant increase in titratable acidity. When evaluating the color of the yogurt, the L*-values were not significantly influenced by CFE supplementation; however, the a*- and b*-values significantly increased with the addition of CFE during storage. The power law and Casson models were applied to assess the flow behavior of CFE-added yogurt samples. The magnitudes of apparent viscosity (ηa,100), consistency index (K), and yield stress (σoc) for 4∼6% CFE yogurt samples were significantly greater than those for the control, indicating that CFE can be used as a thickening agent for yogurt. The sensory test revealed that addition of CFE (2∼4%) to yogurt did not significantly affect the overall scores, but the overall preference score for 6% CFE yogurt was significantly decreased. Based on the data obtained from the present study, we concluded that the concentrations (2∼4%) of CFE could be used to produce a CFE-added yogurt without the significantly adverse effects on the physicochemical and sensory properties.