2, 3(2002)), and the following polymerization of TMSA occurred on the surface of gold particles. Gold nanoparticles were prepared in the presence of 11-mercaptoundecanol(MUD) and subsequently esterified with 2-bromoisobutyryl bromide (BIB) for ATRP initiation (Mandal et al.,NANO lett. Poly(acrylic acid) coated core-shell type of gold and magnetite nanoparticles were prepared by deprotection of poly(trimethylsilyl acrylate)(TMSA) which was polymerized on the gold nanoparticles by ATRP (by using the grafting from method). Preparation and characterization of the core-shell type of nanoparticles We characterized Janus particles by TEM, DLS, and Zeta Potential. Consequently, Janus nanoparticles can self-assemble into micelle-like structures depending on medium conditions such as pH, temperature, concentration and additional salt. This Janus particle can have a surfactant-like structure if the remaining colloid surface has different properties than the tail polymer. The colloid size is approximately 5-10 nm and the functional polymer is on only one side of the colloid. Specifically, we have prepared nanoparticles that have a composite structure consisting of a nanocolloid and a soft material. In previous studies, Janus particles have been prepared for particles on the order of 100s of nanometers, but never before at the 10 nm scale. We examined the PAA coated core shell structure of nanoparticles by TEM, TGA, FT-IR, GPC, DLS, UV/Visible spectroscopy (for gold particles) and Zeta potential measurement and their pH dependent behaviors by DLS, Zeta potential and UV/Visible spectroscopy (for gold particles) at pH values from 10 to 2.Īlso, we have recently developed methods for the synthesis of a new set of functional nanoparticles with asymmetric surface properties "C Janus Particles. Also these carboxylic groups on the surface help in the easy functionalization of the nanoparticles. We can control the aggregation and dispersion by changing pH because of the isoelectric point for PAA(pKa=4.5). In addition, PAA is a well-known and a very useful polymer because of its numerous carboxyl groups. The methods of attaching polymer on the surface of nanoparticles (namely "grafting onto method") tend to lead to a relatively low graft density because of the steric repulsions. ATRP is a well-known technique for creating a narrow polymer distribution which allows us to make core-shell nanoparticles with a precisely designed and high density polymer shell. Poly acrylic acid (PAA)-coated core-shell gold and magnetite nanoparticles were prepared by surface initiated atomic transfer radical polymerization (ATRP) (namely "grafting from method") as has been the recent trend in synthesizing core-shell type nanoparticles. Two forms of functionalization have been employed which resulted in the core shell type and the Janus type nanoparticles. In this report, we present polymer functionalized gold and magnetite nanoparticles. It is very important to prepare nanoparticles with a well defined size distribution and with surface functionalization because of their ferrohydrodynamic behavior. On the other hand, the magnetite nanoparticles can be controlled by an external magnetic field. Because of plasmon behavior, different conditions of aggregation result in different colors which helps us for a visual determination of the aggregation condition of particles. This results in a strong absorption at that wavelength. For particles which are small compared to the wavelength of the incident light, plasmons are excited when light with an appropriate wavelength is shone on them.
#FUNCTIONALIZED CORE SHELL NANOPARTICLES FREE#
Gold nanoparticles display electromagnetic resonance due to collective oscillations of their free electrons known as plasmons. There are undoubtedly still many gains to be made in the synthesis, functionalization, characterization and applications of these systems. These functionalized nanoparticles, prominent among which are gold(Au) and magnetic (Fe3O4) nanoparticles, are applied in a wide range of fields, including drug delivery systems, diagnostics, gene analysis, proteomics, affinity purifications, quantum dots, and the like. In recent years, there has been increasing interest in the potential applications of functionalized nanoparticles, with a concomitant strong scientific focus on their fundamental properties.