Triple-Responsive Pickering Emulsion Stabilized by Core Cross-linked Supramolecular Polymer Particles

Abstract

It is significant to explore multiresponsive Pickering emulsions because of their flexibility in terms of demulsification in comparison with the single stimuliresponsive systems. In this study, we described a tripleresponsive oil-in-water Pickering emulsion that was stabilized by amphiphilic core cross-linked supramolecular polymer particles (CCSPs). For this purpose, β-cyclodextrin-terminated poly(N-isopropylacrylamide) (PNIPAM-β-CD) and azobenzene-capped poly(4-vinylpyridine) (P4VP-azo) were separately synthesized by reversible addition−fragmentation chain transfer polymerization. By virtue of the inclusion interaction between the β-CD host and the azobenzene guest in dimethyl sulfoxide, the amphiphilic supramolecular block copolymer, poly(4-vinylpyridine)-b-poly(N-isopropylacrylamide) (P4VP-b-PNIPAM), was formed. CCSPs were prepared through the combination of the self-assembly of P4VP-b-PNIPAM in the selective solvent, water, and the cross-linking of the P4VP core with 1,4-dibromobutane. Due to thermoresponsiveness of PNIPAM shells and the supramolecular linkages between the cross-linked hydrophobic P4VP core and hydrophilic PNIPAM shells, the as-prepared CCSPs exhibited temperature-, light-, and amantadine hydrochloride guest-triggered morphological transitions. Such triple-responsive morphological transitions gifted CCSPs stabilized oil-in-water Pickering emulsion with flexible demulsification in response to various factors, such as thermo, light, and amantadine hydrochloride or their combinations. Such triple-responsive oil-in-water Pickering emulsion also provided an ideal platform for heterogeneous reactions conducted at the oil−water interface. A large interfacial area and responsive demulsification allowed the reaction to be performed with an efficient and sustainable pattern.

Polymers with advanced architectures as emulsifiers for multi-functional emulsions

“…Gao et al synthesized β-cyclodextrinterminated poly(N-isopropyl acrylamide) (PNIPAM-β-CD) and azobenzene-capped poly(4-vinyl pyridine) (P4VP-azo) that formed supramolecular diblock copolymers through the inclusion interaction between the β-CD host and the azobenzene guest then self-assembled into core-shell polymer particles in the aqueous phase followed by cross-linking of the P4VP core. 125 The core cross-linked supramolecular polymer particles could stabilize o/w emulsion with styrene, benzene, or chloroform as the oil phase. The PNIPAM shells would collapse upon heating, thus triggering demulsification, imparting thermal responsiveness to the emulsions.…”

New Insights into the Formulation and Polymerization of Pickering Emulsions Stabilized by Natural Organic Particles

“…(A) Starch/zein nanocomposites with pH-responsive emulsion behavior (adapted from ref ). (B) Design of temperature, light, and competitive guest sensitive particles based on cyclodextrin (adapted from ref ).…”

Pickering/Non‐Pickering Emulsions of Nanostructured Sulfonated Lignin Derivatives

“…To predict the pH-dependency of adsorption of SEKL/N-SEKL at the xylene interface, two-(WCA, water contact angle) and three-phase (OCA, oil contacta ngles) contact angles of as olid surface( SEKL/N-SEKL)a ta na ir/water and oil/water interface were determined, respectively. [53] WCA defines the wettability of the SEKL surface in different pH environments. The adsorp-tion of SEKL/N-SEKL at the interface is possible only if the equilibrium of at hree-phase contact angle q exists.…”