Asymmetrical Morphology and Performance of Composite Colloidal Particles Controlled via Hydrophilic Comonomer Addition Time in the Presence of Polyvinylidene Fluoride Latex

Abstract

Anisotropic composite latex particles with heteromorphous bowl-like and popcorn-like shapes were fabricated by a general approach: seeded emulsion polymerization. The morphologies of polyvinylidene fluoride@poly(styrene-co-butyl acrylate-co-3-trimethoxysilyl propyl methacrylate) composite particles [PVDF@P(St-co-BA-co-MPS)] could be efficiently controlled by varying the feeding time of hydrophilic MPS. The deformation mechanism of bowl-like particles was largely attributed to the diverse rigidities of the P(St-co-BA-co-MPS) phase from the inhomogeneous cross-linking density formed through changes in the MPS feeding time. During the polymerization, the PVDF crystallization behaviors demonstrated an obvious transformation from unconfined to confined crystallization. Additionally, the chemical properties and morphologies of the particles' surface greatly impacted the hydrophilic−hydrophobic character of the particle films. After the capping of the hydrophilic functional groups of the surface, the contact angle (165°) of the bowl-like particles was much higher than that of the popcorn-like particles (112°) because more caves exist on the former surface, exhibiting a superhydrophobicity.

Synthetic Strategies for Polymer Particles with Surface Concavities

“…Dimpled polymer particles have been conveniently prepared via various polymerization techniques, either seeded polymerization [ 53–93 ] or one‐step polymerization. [ 94–108 ] In most cases, the polymerization recipe involves the use of a cross‐linker (e.g., divinylbenzene (DVB)) or a comonomer that can form rigid shell during polymerization (e.g., 3‐(trimethoxysilyl)propyl methacrylate (TPM)).…”

“…Various seeded polymerization techniques including emulsion polymerization, [ 53–66 ] surfactant‐free emulsion polymerization, [ 67–73 ] and dispersion polymerization [ 74–83 ] have been employed for the formation of dimpled polymer particles with preformed polymer particles as seeds.…”

“…Pan and co‐workers reported the fabrication of bowl‐like and popcorn‐like polyvinylidene fluoride@poly(styrene‐ co ‐butyl acrylate‐ co ‐3‐trimethoxysilylpropyl methacrylate) [PVDF@P(St‐ co ‐BA‐ co ‐MPS)] core–shell latex particles by seeded surfactant‐free emulsion polymerization. [ 73 ] The comonomer MPS was selected since it can be hydrolyzed to form cross‐linkable –OH groups. The rigidity difference in the P(St‐ co ‐BA‐ co ‐MPS) shell caused by the uneven cross‐linking density was responsible for the formation of bowl‐like particles.…”

A strategy for preparing controllable, superhydrophobic, strongly sticky surfaces using SiO2@PVDF raspberry core–shell particles

“…31,32 Furthermore, the CA can be adjusted according to the empty space between the particles. 33,34 In particular, raspberry-shaped particles have a larger volume of empty space than normal particles, which results in a larger water CA. 35,36 Additionally, the surface modication of colloidal particles with uorine groups have signicantly low free energy, thus yielding a structured coating with a larger CA.…”

Revisiting the Classical Emulsion Polymerization: An Intriguing Occurrence of Monodispersed Bowl-Shaped Particles

“…In view of the great potential of BSs in special range of applications, more and more preparation methods have been developed for the large-scale preparation of this kind of particles. Looking back to many publications on the synthesis of BSs in the past over decade, the fabrication methods are mainly divided into the following several kinds: deformation of spherical particles, − microfluidics, and sacrificial templates. , For instance, Huang et al obtained monodisperse single- or multi-cavity and cauliflower-like latex particles by adjusting the position of the phase separation just through change the charging mode of divinylbenzene (DVB). Cao and co-workers precisely prepared bowl-shaped polysilsesquioxane particles due to the flexibility of the shell and the osmotic pressure in combination with centrifugal force.…”