title: Reversible Plasmonic Circular Dichroism via Hybrid Supramolecular Gelation of Achiral Gold Nanorods.
abstract: The fabrication of chiroptical plasmonic nanomaterials such as chiral plasmonic gold nanorods (GNRs) has been attracting great interest. Generally, in order to realize the plasmonic circular dichroism (PCD) from achiral GNRs, it is necessary to partially replace the surface-coated cetyltrimethylammonium bromide with chiral molecules. Here, we present a supramolecular approach to generate and modulate the PCD of GNRs through the hybrid gelation of GNRs with an amphiphilic chiral dendron gelator. Upon gelation, the PCD could be produced and further regulated depending on the ratio of the dendrons to GNRs. It was revealed that the wrapping of the self-assembled nanofibers around the GNRs is crucial for generating the PCD. Furthermore, the hybrid gel underwent a thermotriggered gel-sol and sol-gel transformation, during which the PCD can disappear (solution) and reappear (gel), respectively, and such process can be repeated many times. In addition, the hybrid gel could also undergo shrinkage upon addition of a slight amount of Mg2+ions, during which the PCD disappeared also. Thus, through the gel formation and subsequent metal ion- or temperature-triggered phase transition, PCD can be reversibly modulated. The results not only clarified the generation mechanism of PCD from the achiral GNRs without the chiral modification on the surface but also offered a simple and efficient way to modulate the PCD.
authors.affiliation: Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.|University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Xue
authors.initials: X
authors.lastname: Jin
authors.affiliation: National Center for Nanoscience and Technology, CAS Center for Excellence in Nanoscience , Beijing 100190, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.|National Center for Nanoscience and Technology, CAS Center for Excellence in Nanoscience , Beijing 100190, People's Republic of China.|A Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300072, People's Republic of China.|University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Minghua
authors.identifier: 0000-0002-6603-1251
authors.initials: M
authors.lastname: Liu
keywords: gold nanorod; hydrogels; plasmonic circular dichroism; reversible modulation; self-assembly