Kwon, Seung Ho Xu, Meng Kim, Jinwoo Kim, Eun Ji Lee, Young Jun Jang, Se Gyu Yun, Hongseok Kim, Bumjoon J. 2024-01-19T13:03:27Z 2024-01-19T13:03:27Z 2022-04-03 2021-12 0897-4756 https://pubs.kist.re.kr/handle/201004/115954 Dynamic particles with switchable shapes in response to light have attracted great interest to develop programmable smart materials with superior spatial and temporal resolution. Herein, a facile strategy for light-responsive, shape-changing block copolymer (BCP) particles is developed. Key to this strategy is the design of azobenzene-grafted Au nanoparticles (Au@Azo NPs) as photoswitchable surfactants through photoisomerization of Azo ligands. Under visible light, onion-like polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) BCP particles with PS outer layer form due to the nonpolar nature of trans-Azo ligands, whereas the isomerization to polar cis-Azo surfactants with UV irradiation transforms these spheres into ellipsoids with both PS and P2VP exposed on their surfaces. This light-driven shape change is robust and reversible over multiple irradiation cycles. The reversible shape evolution between spherical and ellipsoidal BCP particles induced by photoactive Au@Azo NP surfactants is elucidated using a cryogenic electron microscope. Furthermore, light-dependent fluorescence and shape of the BCP particles are successfully demonstrated, enabling the visualization of particle shape into an optical signal. English AMER CHEMICAL SOC Light-Active, Reversibly Shape-Shifting Block Copolymer Particles Using Photo-switchable Au Nanoparticle Surfactants Article 10.1021/acs.chemmater.1c03684 1 CHEMISTRY OF MATERIALS, v.33, no.24, pp.9769 - 9779 CHEMISTRY OF MATERIALS 33 24 9769 9779 N scie scopus 000730589100001 2-s2.0-85121107136 Chemistry, Physical Materials Science, Multidisciplinary Chemistry Materials Science Article GOLD NANOPARTICLES FACILE SYNTHESIS POLYMER ASSEMBLIES PHOTOISOMERIZATION AGGREGATION COMPOSITES TRANSITION LOCATION MICELLES