Thermoresponsive polymer coated gold nanoparticles: from MADIX/RAFT copolymerization of N-vinylpyrrolidone and N-vinylcaprolactam to salt and temperature induced nanoparticle aggregation

摘要: In the present contribution, we report MADIX/RAFT polymerization for synthesis of thermoresponsive homo and statistical copolymers N-vinylcaprolactam (NVCL) N-vinylpyrrolidone (NVP). The conditions NVP were optimized using an automated parallel synthesizer these optimal applied preparing with systematical variation in composition. cloud point temperatures (TCP's) aqueous solutions PNVCL P(NVCL-stat-NVP)’s (CP1–CP5) found to be tuneable between 40 °C >95 at 5 mg mL−1. Next, stable colloidal AuNPs coated CP1–CP5 obtained via exchange reaction pre-synthesized citrate stabilized by a direct ‘grafting to’ approach. maximum absorbance wavelength (λmax) surface plasmon resonance (SPR) band size all polymer almost unchanged up 65 (above TCP CP5) MilliQ water which is presumably due electrostatic stabilization residual groups on surface. However, 0.1 M NaCl solution λmax red shifted when heated attributed screening negative charges that suppress enabling T-induced aggregation leading shift SPR band. These may find applications as colorimetric temperature and/or salt sensors.