Novel Strategy of Polymers in Combination with Silica Particles for Reversible Control of Oil–Water Interface

Abstract

Hybrid smart emulsification systems are highly applicable in manipulating oil-in-water (O/W) droplets. Herein, novel switchable block polymers containing both zwitterionic and tertiary amine pendent groups were designed and synthesized to combine with charged silica particles to stabilize the O/W emulsion responsive to pH. This study was carried out in O/W emulsions stabilized with the polymer and silica particles under different pH conditions. The emulsion system was also simulated using molecular dynamics simulation to reveal the mechanism at molecular levels, thus gaining insight into the relationships between the emulsifying properties and the molecular interaction of the mixed system. Upon acidification of the continuous aqueous phase, protonated polymers with excellent hydrophilicity were induced by charged silica particles to cause rapid emulsion coalescence. In alkaline media, the mixed system conversely stabilized the O/ W emulsions, cutting polymer consumption by over three-quarters. The emulsification and demulsification can be switched alternately by tuning the pH conditions. The applications exhibited excellent efficiency in separating heavy oil/water emulsions and proved the high conversion rate in emulsion polymerization. Overall, with this novel strategy to relieve tedious modifications on particle surfaces and massive consumption of polymers, the designed responsive emulsification systems can impart intelligent and controllable chemical reactivity to emulsions on demand in a more affordable and sustainable way.

Recyclable Fe3O4 Nanoparticles Responsive to Temperature for Heavy Oil Viscosity Reduction: Synthesis, Characterization, and Performance

“…pH, CO 2 , N 2 , and other ways that directly contact and interact with emulsions belong to chemical stimuli. Those chemical stimuli often change the properties of the sensitive molecules by triggering minor chemical reactions, thus affecting the macroscopic properties of the materials. , Ma et al synthesized a novel switchable block polymer combined with charged silica particles to stabilize the O/W emulsion responsive to pH. Emulsification and demulsification could be carried out alternately by adjusting the pH value.…”

Dual-responsive polymers synthesized via RAFT polymerization for controlled demulsification and desorption

“…Although intelligent amphiphilic polymers are one of the most potential candidates to achieve the reversible control of oil-water systems, it has been challenging to accurately control the self-assembly of amphiphilic polymers in an aqueous solution using external stimuli, which is crucial to promote sustainable development of the applications involving wastewater treatment, oil-water separation, dye adsorption, targeted release of drugs, and smart interfaces [3][4][5] .…”

“…Substantial work has been done on the synthesis and self-assembly of amphiphilic polymers in aqueous media. A wide range of amphiphilic polymers can be synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, which belongs to the family of reversible-deactivation radical polymerization (RDRP) methods according to IUPAC 5,7 . This polymerization has a good control effect on the molecular weight distribution and is used to control the uniform arrangement of hydrophobic and hydrophilic segments in amphiphilic block polymers.…”