Reversible Clustering of Gold Nanoparticles under Confinement

A limiting factor of solvent‐induced nanoparticle self‐assembly is the need for constant sample dilution in assembly/disassembly cycles. Changes in the nanoparticle concentration alter the kinetics of the subsequent assembly process, limiting optical signal recovery. Herein, we show that upon confining hydrophobic nanoparticles in permeable silica nanocapsules, the number of nanoparticles participating in cyclic aggregation remains constant despite bulk changes in solution, leading to highly reproducible plasmon band shifts at different solvent compositions.L.M.L.-M. and M.G. acknowledge funding from the Spanish MINECO (Grant #MAT2013-46101R). N.C. and S.B. acknowledge financial support from European Research Council (ERC Starting Grant #335078-COLOURATOM). D.M.S., and J.M.T, acknowledge funding from the European Regional Development Fund (ERDF) and the Spanish MINECO (Projects TEC2017-85376-C2-1-R, TEC2017-85376-C2-2-R), and from the ERDF and the Galician Regional Government under agreement for funding the Atlantic Research Center for Information and Communication Technologies (AtlantTIC)