Repeated protrusion of fluorescent pyrene nanorods on the surface of crosslinked poly(allylamine hydrochloride) microcapsules

The ability to prepare micro/nano materials with a stable structure is highly demanded in advanced sciences and technologies. In this work, poly(allylamine hydrochloride)-graft-pyrene microcapsules with a stable structure were obtained by glutaraldehyde crosslinking, which could then be employed as microreactors to protrude 1-pyrenecarboxaldehyde nanorods at low pH. The protrusion length of nanorods (NR) was tuned by the pH value, e.g. shorter NRs and a larger covering density or longer NRs and a lower covering density on the microcapsule surface at higher and lower pHs, respectively. The protruded pyrene NRs showed strong fluorescent emissions on the surface of microcapsules. The NRs could be repeatedly protruded by manipulating the reversible Schiff base formation and hydrolysis.