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Thermoresponsive Gold Polymer Nanohybrids with a Tunable Cross‐Linked MEO 2 MA Polymer Shell
Author(s) -
LaprestaFernández Alejandro,
GarcíaGarcía José Manuel,
París Rodrigo,
HuertasRoa Rafael,
SalinasCastillo Alfonso,
de la Llana Sabrina Anderson,
HuertasPérez José Fernando,
Guarrotxeekane,
CapitánVallvey Luis Fermín,
QuijadaGarrido Isabel
Publication year - 2014
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201400078
Subject(s) - lower critical solution temperature , polymer , dynamic light scattering , materials science , chemical engineering , colloidal gold , methacrylate , nanoparticle , polymerization , absorbance , colloid , precipitation polymerization , thermoresponsive polymers in chromatography , precipitation , light scattering , polymer chemistry , radical polymerization , nanotechnology , chemistry , scattering , copolymer , composite material , organic chemistry , chromatography , optics , engineering , physics , high performance liquid chromatography , reversed phase chromatography , meteorology
Gold nanoparticles (AuNPs) are functionalized with a thermoresponsive polymer shell of a cross‐linked poly(2‐(2‐methoxyethoxy)ethyl methacrylate) (P(MEO 2 MA)). To provide a covalent attachment of the polymer to the NP surface, AuNPs are first modified using butanoic acid to develop the encapsulation with the biocompatible thermoresponsive polymer formed by free‐radical precipitation polymerization. Both the MEO 2 MA concentration and the shell cross‐linking density can be varied and, in turn, the thickness and the shells' free volume can be fine‐tuned. By downscaling the size of the polymeric shell, the lower critical solution temperature (LCST) is decreased. The LCST in the nanohybrids changes from 19.1 to 25.6 °C when increasing the MEO 2 MA content; it reaches almost 26 °C for P(MEO 2 MA) (bulk). The maximum decrease in the volume of the nanohybrids is around 40%, resulting in a modification of the light scattering properties of the system and causing a change in the turbidity of the gel network. The sizes of the nanohybrids are characterized using both transmission electron microscopy and dynamic light scattering measurements. Optical properties of the colloidal systems are determined using the derived count rate measurements as an alternative to absorbance or transmittance measurements, confirming the colloidal stability of the nanohybrid systems.