Light-Responsive, Shape-Switchable Block Copolymer Particles

Abstract

A robust strategy is developed for preparing light-responsive block copolymer (BCP) particles in which shape and color can be actively controlled with high spatial and temporal resolution. The key to achieving light-responsive shape transitions of BCP particles is the design and synthesis of surfactants containing light-active groups (i.e., nitrobenzyl esters and coumarin esters) that modulate the amphiphilicity and interfacial activity of the surfactants in response to light of a specific wavelength. These light-induced changes in surfactant structure modify the surface and wetting properties of BCP particles, affording both shape and morphological transitions of the particles, for example from spheres with an onion-like inner morphology to prolate or oblate ellipsoids with axially stacked nanostructures. In particular, wavelength-selective shape transformation of the BCP particles can be achieved with a mixture of two light-active surfactants that respond to different wavelengths of light (i.e., 254 and 420 nm). Through the use of light-emitting, photoresponsive surfactants, light-induced changes in both color and shape are further demonstrated. Finally, to demonstrate the potential of the light-triggered shape control of BCP particles in patterning features with microscale resolution, the shape-switchable BCP particles are successfully integrated into a patterned, free-standing hydrogel film, which can be used as a portable, high-resolution display.

Transformable Colloidal Polymer Particles with Ordered Internal Structures

“…Responsive morphological transformations of internally ordered colloidal polymer particles are of great interest due to their potential as smart nanomaterials for applications in sensors, detection, anti-fake, etc. [8,32,33] 3D confined thermal-or solvent-annealing enables morphological transformations of nanostructured colloidal polymer particles in a controllable manner. [34,35] Previously, we have demonstrated how interfacial interaction drives BCP segment orientation (e.g., from parallelto concentric-lamellar) within a 3D soft confined space upon solvent annealing.…”

“…[27] Recently, Kim et al extend this strategy by using a light responsive surfactant that can dynamically tune the interfacial interaction. [32] Besides, a switchable transformation between pupa-like and faveolated particles by changing the location of pH and/or temperature responsive additives were reported. [33,36] The addition or removal of additives can vary the volume fraction, thereby inducing the transformations in the internal structure of the particles.…”

Light‐Controlled Nanosystem with Size‐Flexibility Improves Targeted Retention for Tumor Suppression

“…Moreover, light has been considered as a flexible, precise, and non‐invasive element for “smart” therapy. [ 24–26 ] Majority of the light‐responsive materials is sensitive to ultraviolet, such as azobenzenes, [ 27 ] nitrobenzenes, [ 28 ] spiropyrans, [ 29 ] and diarylenes. [ 30 ] However, limitations of transformation and application still remain, because of the poor tissue penetration.…”

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

“…The external stimulus response provides a simple pathway for the controllable transformation of particle morphology on demand. [ 23,24 ] It has been reported that the use of pH, [ 10,25 ] temperature, [ 26,27 ] light, [ 28,29 ] and electric field [ 30–32 ] can cause changes in particles shape. For example, Weck et al.…”