Electroinduced Reconfiguration of Complex Emulsions for Fabrication of Polymer Particles with Tunable Morphology

Abstract

Continuous morphological control of anisotropic particles is always an important challenge in the field of materials. In this study, a new strategy for continuous fabrication of polymer particles with various morphologies induced by electricity is reported using complex emulsions as template. A synthetic electro‐responsive surfactant containing ferrocene group is used to prepare complex emulsions, which contain a polymerizable monomer as inner phase. With the increasing time of electrical stimulation on the complex emulsions, hollow, hemispherical, mushroom‐like, and spherical particles are constructed successively after photopolymerization. The Marangoni effect caused by the heterogeneity in the interfacial tension at the droplet surface is the reason for the reconfigurable morphology of the complex emulsion. The controllable complex emulsions by electricity present a versatile platform for constructing fine control of the microstructure and shape anisotropy of particles having customized shapes and functionalities, opening a new possibility for designing sophisticated architectures.

Dynamic In Situ Monitoring of the Salt Counter-ion Effect on Surfactant Effectiveness Using Reconfigurable Janus Emulsions

“…Selectively influencing their effectiveness then allows to dynamically and controllably alter the interfacial tension equilibrium and thus droplet morphology. To this end, a series of active surfactants have been developed that can be selectively attached to specific droplet interfaces, e.g., in order to target specific stimuli, such as light, electric or magnetic fields, − environmental contaminants, , biomacromolecules, or bacteria . Based on the unique chemical-morphological-optical coupling inside reconfigurable complex droplets and depending on a fine-adjustment of the droplets’ starting morphology, marginal variations of the interfacial tension balance can then cause significant variations of the macroscopic optical properties of the emulsion.…”

Recent Progress toward Physical Stimuli‐Responsive Emulsions

“…[ 76 ] Guo and co‐workers achieved continuous preparation of polymer particles with different morphologies by the development of electricity‐responsive complex emulsions as template (Figure 9). [ 77 ] The complex emulsions were stabilized by a mixture of surfactants, in which the ferrocene group in the surfactant molecules can be oxidized and reduced by an applied electric field, so that the hydrophilicity of the surfactant was changed, and then the topological structure of the emulsion can be changed upon electric field.…”

“…In fact, microwave, [62][63][64][65][66] ultrasonic, [67][68][69][70][71][72] external electric field [73][74][75][76][77] have also been investigated for the control of emulsion properties, such as morphology and stability. As a clean, cheap, and convenient way to provide heat, microwave has high efficiency and low time consumption in heat generation.…”

Morphology‐Dependent Aggregation‐Induced Emission of Janus Emulsion Surfactants

“…[13] As a result, Janus droplets exhibit dynamic internal morphologies, and small variations in surfactant composition or effectiveness can transduce into significant changes in their internal geometry. This chemical-morphological coupling inside Janus emulsions, that is, the reversible tunability of their internal geometry as a function of their chemical environment has entailed a series of transformative application concepts, including their use as versatile refractory optical elements, [14][15][16] liquid templates for the generation of precision objects, [17][18][19] and as powerful sensors for a series of chemical and biological analytes. [20][21][22][23][24][25] Particularly the implementation of Janus emulsions as novel modular signal amplifiers in liquid biosensing platforms requires an efficient transduction of chemicallyinduced morphological transitions into a readable signal output.…”