Janus-Like Single-Chain Polymer Nanoparticles as Two-in-One Emulsifiers for Aqueous and Nonaqueous Pickering Emulsions

Abstract

The exploration of Pickering emulsions is very significant owing to their versatile and important applications in many scopes. In this study, synthesis of a novel kind of single-chain polymer nanoparticle (SCPN) and its stabilized Pickering emulsions were demonstrated. To this end, linear-dendritic diblock copolymers consisting of poly­((2-dimethylamino) ethyl methacrylate) (PDMAEMA) blocks and four-generation dendritic aliphatic polyester blocks (G4) have been first synthesized by the combination of click chemistry and reversible addition-fragmentation chain transfer (RAFT) polymerization reaction. The subsequent intramolecular cross-linking of the PDMAEMA block of PDMAEMA-b-G4 copolymers in DMF using 1,4-diiodobutane as cross-linkers afforded Janus-like SCPNs that exhibited a cross-linked PDMAEMA head tethered by a short dendritic tail. The molecular weight and distribution together with the structure of polymers were carefully characterized by GPC and NMR spectroscopy. By the employment of the as-synthesized Janus-like SCPNs as Pickering emulsifiers, aqueous and nonaqueous Pickering emulsions including water-in-oil and oil-in-oil as well as ionic liquid-in-oil were generated. Under the same conditions, it was found that the long-term stabilities of Pickering emulsions stabilized by Janus-like SCPNs were superior to those of Pickering emulsions stabilized by their linear quaternized PDMAEMA-b-G4 by CH3I analogous.

Single-Chain Polymer Nanoparticles for Addressing Morphologies and Functions at the Nanoscale: A Review

“…Also Gao et al synthesized Janus-like SCNPs and employed them as pickering emulsifiers for aqueous and nonaqueous emulsions (Figure 8e). 65 They designed linear−dendritic diblock copolymers consisting of poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) blocks and four-generation dendric aliphatic polyester blocks (G 4 ). The PDMAEMA block of PDMAEMA-b-G 4 undergoes a subsequent intramolecular cross-linking by 1,4-diiodobutane as cross-linker.…”

Polymer-Derived Janus Particles at Multiple Length Scales

“…The stabilized emulsion morphology could be readily varied by using the example colloidal dimer composed of dendritic aliphatic polyester and intramolecularly cross-linked poly((2-dimethylamino)ethyl methacrylate). 89 Electrostatic-mediated intramolecular cross-linking is also effective for orthogonal intramolecular cross-linking as demonstrated in diblock copolymer of poly(isoprene)-block-poly(2vinylpyridine) (PI-b-P2VP), 90 where PI and P2VP were modified with 2-mercaptoethylamine hydrochloride and iodoethane to introduce electrostatic interactions prior to the cross- linking. 1,6-Hexanediisothiocyanate and 1,5-diiodopentane were used to selectively cross-link the two modified blocks, respectively.…”

“…The amphiphilic colloidal dimer afforded a robust platform to functionalize emulsion interfaces. The stabilized emulsion morphology could be readily varied by using the example colloidal dimer composed of dendritic aliphatic polyester and intramolecularly cross-linked poly­((2-dimethylamino)­ethyl methacrylate) …”

Formation of n-Hexane-in-DMF Nonaqueous Pickering Emulsions: ABC Triblock Worms versus AB Diblock Worms

“…Nonaqueous Pickering emulsions usually refer to systems in which water of aqueous Pickering emulsions is replaced by an oil (polar or apolar), ,− which are of great importance but relatively less studied in the past. Compared with water/oil interfaces, the oil/oil interfaces usually exhibit a low interfacial tension. ,, A low interfacial tension is not helpful for stable adsorption of particles at the liquid/liquid interface. Consequently, custom-made Pickering emulsifiers might be required for a specific oil–oil system.…”

“…Compared with water/oil interfaces, the oil/oil interfaces usually exhibit a low interfacial tension. 45,48,49 A low interfacial tension is not helpful for stable adsorption of particles at the liquid/liquid interface. Consequently, custom-made Pickering emulsifiers might be required for a specific oil−oil system.…”