Temperature-modulated quenching of quantum dots covalently coupled to chain ends of poly(N-isopropyl acrylamide) brushes on gold.
A thermo-responsive polymer/quantum dot platform based on poly(N-isopropyl acrylamide) (PNIPAM) brushes 'grafted from' a gold substrate and quantum dots (QDs) covalently attached to the PNIPAM layer is presented. The PNIPAM brushes are grafted from the gold surface using an iniferter-initiated controlled radical polymerization. The PNIPAM chain ends are functionalized with amine groups for coupling to water-dispersible COOH-functionalized QDs. Upon increasing the temperature above the lower critical solution temperature (LCST) of PNIPAM the QD luminescence is quenched. The luminescence was observed to recover upon decreasing the temperature below the LCTS. The data obtained are consistent with temperature-modulated thickness changes of the PNIPAM layer and quenching of the QDs by the gold surface via nonradiative energy transfer.
Materials Science and Technology of Polymers, Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Oya
O
Tagit
Nikodem
N
Tomczak
Edmondo M
EM
Benetti
Yanina
Y
Cesa
Christian
C
Blum
Vinod
V
Subramaniam
Jennifer L
JL
Herek
G
G
Julius Vancso
D000180:Acrylic Resins / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D045663:Quantum Dots; D013499:Surface Properties; D013696:Temperature
D000180:Acrylic Resins; D046911:Macromolecular Substances; C052970:poly-N-isopropylacrylamide; D006046:Gold