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Thermoresponsive Gold Nanoparticles with Positive UCST‐Type Thermoresponsivity
Author(s) -
Liu Fangyao,
Agarwal Seema
Publication year - 2015
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201400497
Subject(s) - upper critical solution temperature , colloidal gold , raft , polymerization , polymer chemistry , chain transfer , cloud point , materials science , nanoparticle , colloid , lower critical solution temperature , chemical engineering , chemistry , copolymer , nanotechnology , radical polymerization , aqueous solution , polymer , organic chemistry , engineering
Trithiocarbonate end‐functionalized poly( N ‐acryloylglycinamide) (PNAGA), synthesized via reversible addition–fragmentation transfer (RAFT) polymerization of different molecular weights, is grafted onto gold nanoparticles (AuNPs) by ligand exchange in phosphate‐buffered saline. The PNAGA‐grafted AuNPs display upper critical solution temperature (UCST)‐type transitions: stable colloidal distribution and aggregation above and below the cloud points, respectively. Cloud points of PNAGA are not affected by the grafting procedure, and PNAGA@AuNPs show similar cloud points as that of the trithiocarbonate end‐functionalized free‐PNAGAs used for grafting. The UCST‐type phase transition is reversible for many cycles. The reversible control of the phase transition is proved by turbidity measurements and UV–vis spectroscopy, as well as by transmission electron microscopy (TEM).