Engineering hybrid microgels as particulate emulsifiers for reversible Pickering emulsions

Thermo-responsive microgels are unique stabilizers for stimuli-sensitive Pickering emulsions that can be switched between the state of emulsification and demulsification by changing the temperature. However, directly temperature-triggering the phase inversion of microgel-stabilized emulsions remains a great challenge. Here, a hybrid poly(N-isopropylacrylamide)-based microgel has now been successfully fabricated with tunable wettability from hydrophilicity to hydrophobicity in a controlled manner. Engineered microgels are synthesized from an inverse emulsion stabilized with hydrophobic silica nanoparticles, and the swelling-induced feature can make the resultant microgel behave like either hydrophilic or hydrophobic colloids. Remarkably, the phase inversion of such microgel-stabilized Pickering emulsions can be in situ regulated by temperature change. Moreover, the engineered microgels were capable of stabilizing water-in-oil Pickering emulsions and encapsulation of enzymes for interfacial bio-catalysis, as well as rapid cargo release triggered by phase inversion.

Hybrid poly(N-isopropylacrylamide)-based microgels are templated from inverse Pickering emulsions, and the tunable wettability renders as-prepared emulsions with reversible feature.     

Synthesis of Janus Particle Arrays and Janus Films through an Interfacial Polymerization Method

Russian Journal of Physical Chemistry A - We report the fabrication of Janus particle arrays and Janus films through the combination of selfassembly of spheres on a water surface and interfacial...     

Stimuli-responsive microemulsions: State-of-the-art and future prospects

Over the last decade, stimuli-responsive microemulsions, that is, those that switch between stable and unstable states in response to certain stimuli, have attracted considerable attention because of their unique properties and potential for diverse applications. Herein, we highlight the recent advances in the development of microemulsions responsive to external triggers such as pH, redox reactions, light, CO₂ gas, magnetic field and temperature; discuss the corresponding responses; and reveal important composition–microstructure–macroscopic property relationships to suggest future research directions and potential applications.     

The synthesis and structure of pyridine-oxadiazole iridium complexes and catalytic applications:Non-coordinating-anion-tuned selective C—N bond formation

Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography.The designed iridium.complexes revealed surprisingly high catalytic activity in C-N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions.In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols,N,N'-(phenylmethylene)dibenzamide products we re unexpectedly isolated under non-coordinating anion conditions,whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions.The mechanism explorations excluded the possibility of"silver effect"(silver-assisted or bimetallic catalysis)and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions.This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C-N bond formation.     

Smart Emulsions Stabilized by a Multi-headgroup Surfactant Tolerant to High Concentrations of Acids and Salts

Retaining emulsions stable at high acidity and salinity is still a great challenge. Here, we report a novel multi-headgroup surfactant (C₃H₇−NH⁺(C₁₀COOH)₂, di-UAPAc) which can be reversibly transformed among cationic, anionic and zwitterionic forms upon pH variation. Stable oil-in-dispersion (OID) emulsions in strong acidity (pH=2) can be co-stabilized by low concentrations of di-UAPAc and silica nanoparticles. High salinity at pH=2 improves the adsorption of di-UAPAc on silica particles through hydrogen bonding, resulting in the transformation of OID emulsions into Pickering emulsions. Moreover, emulsification/demulsification and interconversion between OID and Pickering emulsions together with control of the viscosity and droplet size can be triggered by pH. The present work provides a new protocol for designing surfactants for various applications in harsh aqueous media, such as strong acidity and high salinity, involved in oil recovery and sewerage treatments.     

High strength chitin nanocrystal/alginate filament prepared by wet-spinning in “green” coagulating bath

Cellulose - Chitin nanocrystals (ChNCs) are an alternative biomaterial of exceptional mechanical stiffness, biocompatibility and sustainability. Wet-spinning is a convenient pathway to control...     

Surface and interfacial properties of 1,3-dialkyl glyceryl ether hydroxypropyl sulfonates as surfactants for enhanced oil recovery

A series of double-chain anionic surfactants, 1,3-dialkyl glyceryl ether hydroxylpropyl sulfonates (diC_mGE-HS, m?=?8, 10, 12), were synthesized from renewable materials. These surfactants possess very low γ_cmc (～25?mN/m) at 25°C, and their mixtures with conventional surfactants can reduce Daqing crude oil/connate water IFT to ultralow at 45°C in wide total concentration range (0.625-10?mM) in the presence of 0.5?wt.% Na₂CO₃. It seems that diC₁₂GE-HS behaves as a hydrophobic component, whereas diC₁₀GE-HS and diC₈GE-HS behave as hydrophilic components in these mixtures. The mixtures also exhibit high resistance against adsorption by sandstone and good ability of keeping sandstone surface water-wet.     

Conjugated Carbazole-Based Schiff Bases as Photoinitiators: From Facile Synthesis to Efficient Two-Photon Polymerization

Exploration of simple and economical synthetic routes to construct active two-photon initiators (2PIs) with long conjugation length is highly desirable to promote the development of two-photon-induced photopolymerization technology. In this article, several conjugated carbazole-based derivatives containing N=C bonds as π bridges and electron donor/acceptor groups were prepared through one-step Schiff base reaction. The structure–activity relationship was systematically investigated through calculations and experimental tests. The results showed that compared to the D-π-D-π-D molecules, the A-π-D-π-A molecules exhibited stronger charge transfer, which induce redshifted linear absorption and enhanced two-photon absorption at 800 nm. The 2PIs displayed aggregation-induced emission property and show potential for the fabrication of luminescent microdevices. In two-photon-induced microfabrication tests, the formulations containing novel 2PIs exhibited lower threshold energy than the widely used commercial photoinitiator Irgacure 369 and the two-photon resists IP-L is the brand name of the two-photon resist from Nanoscribe, specially designed for nanoscribe's laser lithography systems. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2692–2700     

Rational design of MoSe2-rGO-CNTs flower-like heterostructures for efficient acidic hydrogen evolution

Journal of Solid State Electrochemistry - The development of transition metal-based catalysts for hydrogen evolution reaction with high active and stable performance is becoming an important means...     

Theoretical Investigation on the Structural and Spectroscopic Properties of “Cross” [Anthraquinone-Diamine/Diimine-Pt] Complexes

Russian Journal of Physical Chemistry A - The Frontier molecular orbitals, UV–Vis absorption spectra, electron excitation properties, and triplet excited states of 1 and 2 were investigated...