Light-Sculpted Azopolymer Colloids: From Patchy Spheres to Porcupine and Pineapple Morphologies

TL;DR

This paper introduces a light-controlled method to transform azopolymer colloids into complex 3D shapes, enabling programmable morphologies and altered hydrodynamic behaviors for advanced material applications.

Contribution

It demonstrates a novel optical technique to create and control complex colloidal shapes using polarization, supported by a geometric model and flow simulations.

Findings

Linear polarization produces porcupine-like particles with elongated features.

Circular polarization results in sea-pineapple shaped deformations.

Morphologies significantly influence colloidal hydrodynamics and transport properties.

Abstract

A simple optical strategy to transform patchy PMMA azopolymer composite nanoparticles into complex, fully three-dimensional morphologies using controlled laser polarization is presented. The particles consist of a PMMA core decorated with nanoscale azopolymer patches that undergo localized photofluidization upon trans cis isomerization. Linear polarization drives directed mass transport within each patch, producing elongated super-cones that collectively yield porcupine like particles, whereas circular polarization generates isotropic bump deformations reminiscent of sea-pineapple structures. A nonlinear, volume-conserving geometric model quantitatively reproduces the patch-to-filament transition. Brownian and Jeffery-flow simulations reveal that these photoinduced morphologies dramatically alter hydrodynamic behavior, leading to enhanced anisotropic diffusion, reduced rotational randomization, and polarization-dependent transport amplification in shear flow. This light-driven, reversible sculpting method provides a versatile route to programmable colloidal shapes and highlights geometry as a powerful control parameter for microscale transport, active materials, and soft-matter physics.