Architecture and Performance of Raspberry-like Colloidal Particle Clusters via Self-Assembly of in Situ Generated Janus Particles

Uniform raspberry-like poly­(vinylidene fluoride)/polystyrene (PVDF/PS) complex colloidal particle clusters (CCPCs) with PVDF seed particles protruding outward are fabricated by a novel and one-step approach: soap-free seeded emulsion polymerization following single-electron transfer radical polymerization (SET-RP) mechanism. The driving force from different hydrophobicity values between PVDF and PS induces the self-assembly of the first formed Janus particles, which can be caught because of the relatively low rate of SET-RP, and then Pickering emulsion polymerization performs continuously because of the presence of the unreacted St monomers to form the CCPCs. In contrast, the raspberry-like CCPCs cannot be achieved via a relatively high rate of conventional radical polymerization. In addition, the static water contact angle of the latex nanocoating prepared with the obtained raspberry-like CCPCs is 169.6° and remains at 155° after ultraviolet (UV) irradiation for 6 h. Therefore, it is expected to lead to superhydrophobic and anti-UV functional coatings

Intriguing Morphology Evolution from Noncrosslinked Poly(<i>tert</i>-butyl acrylate) Seeds with Polar Functional Groups in Soap-Free Emulsion Polymerization of Styrene

Herein, we demonstrate a facile approach to prepare anisotropic poly­(<i>tert</i>-butyl acrylate)/polystyrene (P<i>t</i>BA/PS) composite particles with controllable morphologies by soap-free seeded emulsion polymerization (SSEP). In the first step, noncrosslinked P<i>t</i>BA seeds with self-stabilizing polar functional groups (e.g., ester groups and radicals) are synthesized by soap-free emulsion polymerization. During the subsequent SSEP of styrene (St), PS bulges are nucleated on the P<i>t</i>BA seeds due to the microphase separation confined in the latex particles. The morphology evolution of P<i>t</i>BA/PS composite particles is tailored by varying the monomer/seed feed ratio, polymerization time, and polymerization temperature. Many intriguing morphologies, including hamburger-like, litchi-like, mushroom-like, strawberry-like, bowl-like, and snowman-like, have been acquired for P<i>t</i>BA/PS composite particles. The polar groups on the P<i>t</i>BA seed surface greatly influence the formation and further merging of PS/St bulges during the polymerization. A possible formation mechanism is proposed on the basis of experimental results. These complex composite particles are promising for applications in superhydrophobic coatings