title: Laser Flash Photolysis of Au-PNIPAM Core-Shell Nanoparticles: Dynamics of the Shell Response.
abstract: Hydrophobic forces play a key role in the processes of collapse and reswelling of thermoresponsive polymers. However, little is known about the dynamics of these processes. Here, thermoresponsive poly(N-isopropylacrylamide)-encapsulated gold nanoparticles (Au-PNIPAM) are heated via nanosecond laser flash photolysis. Photothermal heating via excitation of the localized surface plasmon resonance of the Au nanoparticle cores results in rapid PNIPAM shell collapse within the 10 ns pulse width of the laser. Remarkably, reswelling of the polymer shell takes place in less than 100 ns. A clear pump fluence threshold for the collapse of the PNIPAM shell is demonstrated, below which collapse is not observed. Reswelling takes longer at higher laser intensities.
authors: School of Chemistry and Bio21 Institute, University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors: Sean
authors: S
authors: Murphy
authors: School of Chemistry and Bio21 Institute, University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors: Sarah
authors: S
authors: Jaber
authors: School of Chemistry and Bio21 Institute, University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors: Cameron
authors: C
authors: Ritchie
authors: Physical Chemistry I, Heinrich-Heine-University Düsseldorf , 40204 Düsseldorf, Germany.
authors: Matthias
authors: M
authors: Karg
authors: School of Chemistry and Bio21 Institute, University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors: Paul
authors: P
authors: Mulvaney