Multilayered structures are pervasive in biological systems where nature is able to precisely adjust the morphology, shape, and functionality of nanomaterials to exhibit highly specific properties. This unique ability has long motivated researchers to strive for similar control in synthetic materials in order to tailor macroscopic properties. We herein report a bio-inspired approach to synthetic multilayered block copolymer nanoparticles that represent a first step towards new colloidal materials with tunable structural color.Inspired by the lamellar structure of iridophor cells, which are responsible for the structural color of certain marine species, we developed a new facile strategy to access multilayered block copolymer nanoparticles that exhibit a dynamic, pH-triggered shape change. Elongated particles with an axially stacked lamellae structure are selectively prepared by utilizing functional surfactants to control the phase separation of symmetric PS-b-P2VP in dispersed droplets. Varying the overall molecular weight of the block copolymer or blending in equal amounts of the respective homopolymers allows for tuning of aspect ratio and domain spacing of the ellipsoids. Crosslinking of the P2VP domains then results in multifunctional particles that not only combine an overall shape anisotropy with a well-defined internal morphology, but also display reversible anisotropic swelling due to pH-dependent stretching/shrinking of the elongated particles along the long axis. Due to the corresponding change in refractive index of the P2VP layers, such particles are promising with regards to their utilization as tunable colloidal Bragg reflectors.

Bio-inspired colloidal multilayer materials: Dynamic, shape changing nanoparticles towards tunable structural color

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.