Polymer colloidal nanoparticles

Once the proper conditions to obtain the polymer colloidal nanoparticles are identified, the particles must be stabilized. This is usually achieved either by the elimination of the polymer solvent by evaporation or by chemical cross-linking of the polymer as it is the case with proteins. ... 

Particularly attractive for numerous bioanalytical applications are colloidal metal (e.g., gold) and semiconductor quantum dot nanoparticles. The conductivity and catalytic properties of such systems have been employed for developing electrochemical gas sensors, electrochemical sensors based on molecular- or polymer-functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme-based electrodes, immunosensors, and DNA sensors. Advances in the application of molecular and biomolecular functionalized metal, semiconductor, and magnetic particles for electroanalytical and bio-electroanalytical applications have been reviewed by Katz et al. [142]. 

Zhou Y, Itoh H, Uemura T, Naka K, Chujo Y (2002) Preparation, optical spectroscopy, and electrochemical studies of novel pi-conjugated polymer-protected stable PbS colloidal nanoparticles in a nonaqueous solution. Langmuir 18 5287-5292... 

Combination of static and dynamic laser light scattering is also useful to determine not only the size distribution but also the particle structure of polymer colloids such as the adsorbed surfactant layer thickness [73] and the formation of nanoparticles [74,75]. A recently developed method of determining the density of polymer particles is outlined below to illustrate the usefulness of laser light scattering as a powerful analytical tool for investigating more sophisticated colloidal problems [76-78]. 

Spontaneous formation of nanoparticles can be achieved by taking advantage of the solubility and gelling properties of a dissolved polymer. Usually, the step allowing polymer colloidal particles to form is reversible, and it is necessary to complete the procedure by a second step required to stabilize the particles. 

Nanoparticles can be characterized by all the different physico chemical techniques that apply for polymer colloids. Concerning the development procedure of nanoparticles as drug carriers, the main physico chemical parameters that are investigated are the shape, the size, the surface properties, the density, and the concentration of the particles.f The size as well as the size distribution are important parameters to be determined to achieve safe intravenous administration. Surface properties are also important to consider as... 

The environmentally benign, nontoxic and nonflammable fluids water and carbon dioxide (CO2) are the two most abundant and inexpensive solvents on earth. Vater-in-CO2 (W/C) or C02-in-water (C/W) dispersions in the form of microemulsions and emulsions offer new possibilities in waste minimization for the replacement of organic solvents in fields including chemical processing, pharmaceuticals, and microlectronics for solubilization and separations (e.g., proteins, ions, heavy metals), particle formation, enzymatic catalysis, organometallic catalysis, and synthesis of polymer colloids and inorganic nanoparticles (2,13,11). 

Ram M. K., Yavuz O., and Aldissi M., Gas sensors based on ultrathin films of conducting polymers, in Colloidal Nanoparticles in Biotechnology, ed. Abdelhamid Elaissari (New Jersey John Wiley Sons, 2008), 223-245. 

A. Ramanaviciene, W. Schuhmann, and R. Ramanavicius, AFM study of conducting polymer polypyrrole nanoparticles formed by redox enzyme - glucose oxidase - initiated polymerisation, Colloid Surf. B., 48(2), 159-166 (2006). 

Kumbhar, D. and V. Pokharkar. Physicochemical investigations on an engineered lipid-polymer hybrid nanoparticle containing a model hydrophilic active, zidovudine. Colloid Surface A, 436 (2013) 714—725. 

Assembly of Nanoparticles onto the Surface of Polymer Colloids Throughout Emulsion Polymerization ... 

Muller and coworkers prepared disc-like polymer Janus particles from assembled films of the triblock copolymer SBM and, after hydrolysis of the ester groups into methacrylic acid units, used these as Pickering stabilizer in the soap-free emulsion polymerization of styrene and butyl acrylate [111]. Armes and coworkers described the synthesis of PMMA/siUca nanocomposite particles in aqueous alcoholic media using silica nanoparticles as stabilizer [112], extending this method to operate in water with a glycerol-modified silica sol [113, 114]. Sacanna showed that methacryloxypropyltrimethoxysilane [115] in the presence of nanosized silica led to spontaneous emulsification in water, which upon a two-step polymerization procedure afforded armored particles with an outer shell of PMMA [116]. Bon and coworkers demonstrated the preparation of armored hybrid polymer latex particles via emulsion polymerization of methyl methacrylate and ethyl methacrylate stabilized by unmodified silica nanoparticles (Ludox TM O) [117]. Performance of an additional conventional seeded emulsion polymerization step provided a straightforward route to more complex multilayered nanocomposite polymer colloids (see Fig. 14). 

The behavior of nanoparticles at soft interfaces and their ability to adhere to these strongly has great potential for further studies, especially in the area of solids-stabilized emulsion polymerization. The ability to control and understand mechanistically this process will allow the design of innovative hybrid polymer colloids. 

Fig. 10 TEM images (scale bars. 100 nm) of (a) PMMA latex armored with Ludox silica nanoparticles. Multilayered nanocomposite polymer colloids with (b) a hairy outer layer of polyacrylonitrile, and (c) a soft shell of poly(n-butyl acrylate). Reproduced from [66] with permission of American Chemical Society...

Hybrids from Polymer Colloids and Metallic Nanoparticles ... 

HYBRIDS FROM POLYMER COLLOIDS AND METALLIC NANOPARTICLES... 

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