The semibatch emulsifier-free emulsion copolymerization of methyl methacrylate(MMA and butyl acrylate (BA) in the presence of 2-hydroxyethyl methacrylate (HEMA)initiated by K2S2O8 (PSP) was studied. The latex particle...The semibatch emulsifier-free emulsion copolymerization of methyl methacrylate(MMA and butyl acrylate (BA) in the presence of 2-hydroxyethyl methacrylate (HEMA)initiated by K2S2O8 (PSP) was studied. The latex particles can maintain an appreciablestability during the emulsifier-free emulsion copolymerization of MMA and BA in thepresence of HEMA The average particle diameter increase with an increase of totalsolids content, HEMA content, PSP content, ioniC strength of the system and monomerfeed rate, and decrease with the monomer feed ratio From 3/1(MMA/BA;molar ratio.)to1/3. The stability of this reaction system is improved by adding HEMA as nonioniccomonomer High solids content (50%) latex with monodisperse particle can beobtained using this process.展开更多
We report on the fabrication of a class of surface-enhanced Raman scattering(SERS)active thermometers,which consists of60 nm gold nanoparticles,encoded with Raman-active dyes,and a layer of thermoresponsive poly(N-iso...We report on the fabrication of a class of surface-enhanced Raman scattering(SERS)active thermometers,which consists of60 nm gold nanoparticles,encoded with Raman-active dyes,and a layer of thermoresponsive poly(N-isopropylacrylamide)(PNIPAM)brush with different chain lengths.These SERS-active nanoparticles can be optimized to maintain spectrally silent when staying as single particles in dispersion.Increasing temperature in a wide range from 25 to 55°C can reversibly induce the interparticle self-aggregation and turn on the SERS fingerprint signals with up to 58-fold of enhancement by taking advantage of the interparticle plasmonic coupling generated in the process of thermo-induced nanoparticles self-aggregation.Moreover,the most significative point is that these SERS probes could maintain their response to temperature and present all fingerprint signals in the presence of a colored complex.However,the UV-Vis spectra can distinguish the differences faintly and the solution color shows little change in such complex mixture.This proof-of-concept and Raman technique applied here allow for dynamic SERS platform for onsite temperature detection in a wide temperature range and offer unique advantages over other detection schemes.展开更多
文摘The semibatch emulsifier-free emulsion copolymerization of methyl methacrylate(MMA and butyl acrylate (BA) in the presence of 2-hydroxyethyl methacrylate (HEMA)initiated by K2S2O8 (PSP) was studied. The latex particles can maintain an appreciablestability during the emulsifier-free emulsion copolymerization of MMA and BA in thepresence of HEMA The average particle diameter increase with an increase of totalsolids content, HEMA content, PSP content, ioniC strength of the system and monomerfeed rate, and decrease with the monomer feed ratio From 3/1(MMA/BA;molar ratio.)to1/3. The stability of this reaction system is improved by adding HEMA as nonioniccomonomer High solids content (50%) latex with monodisperse particle can beobtained using this process.
基金supported by the Fundamental Research Funds for the Central Universities
文摘We report on the fabrication of a class of surface-enhanced Raman scattering(SERS)active thermometers,which consists of60 nm gold nanoparticles,encoded with Raman-active dyes,and a layer of thermoresponsive poly(N-isopropylacrylamide)(PNIPAM)brush with different chain lengths.These SERS-active nanoparticles can be optimized to maintain spectrally silent when staying as single particles in dispersion.Increasing temperature in a wide range from 25 to 55°C can reversibly induce the interparticle self-aggregation and turn on the SERS fingerprint signals with up to 58-fold of enhancement by taking advantage of the interparticle plasmonic coupling generated in the process of thermo-induced nanoparticles self-aggregation.Moreover,the most significative point is that these SERS probes could maintain their response to temperature and present all fingerprint signals in the presence of a colored complex.However,the UV-Vis spectra can distinguish the differences faintly and the solution color shows little change in such complex mixture.This proof-of-concept and Raman technique applied here allow for dynamic SERS platform for onsite temperature detection in a wide temperature range and offer unique advantages over other detection schemes.
