Shape control of monodisperse cone-shaped particles by tuning the phase behavior of polymer blends within evaporative emulsion

Abstract

Precise control of the shape and nanostructure of block copolymer (BCP) particles are of great interest for their shape-dependent physical properties. Here, we exploit the blend of poly(styrene-$block$-1,4-butadiene) (PS-$b$-PB) BCP and poly(methylmethacrylate-$statistical$-(4-acryloylbenzophenone)) (P(MMA-$stat$-4ABP)) sCP within the colloidal confinements to develop a series of particles with different symmetry. The key strategy for tuning the particle shape is to systematically control the incompatibility between the BCP and sCP by varying the mole fraction of 4ABP in sCPs ($\phi_{4ABP}$) and the volumetric ratio of sCPs in total blend ($f_{sCP}$). The particles were produced by membrane emulsification method to have monodisperse particle size and shape, and the particle shape can be tuned sequentially from striped ellipsoid to Janus-sphere, to cone-shaped with the increase of $\phi_{4ABP}$ and $f_{sCP}$. In particular, the shape-anisotropy of cone-shaped particles was systematically controlled by varying the size and Janusity, which is supported by quantitative calculation from the modified theoretical model. Furthermore, the importance of the shape control of monodispersed cone-shaped particles was demonstrated by investigating the colloidal coating property of these particles.