@article {1040,
	title = {Laser-light-scattering study of internal motions of polymer chains grafted on spherical latex particles},
	journal = {Journal of Physical Chemistry B},
	volume = {108},
	number = {48},
	year = {2004},
	note = {ISI Document Delivery No.: 875JUTimes Cited: 6Cited Reference Count: 35},
	month = {Dec},
	pages = {18479-18484},
	type = {Article},
	abstract = {Using atom-transfer radical polymerization, we have prepared core-shell particles by grafting thermally sensitive poly(N-isopropylacrylamide) (PNIPAM) chains on a spherical polystyrene latex core (with a radius of similar to287 nm) via the "grafting-from" approach. As the temperature increases from 25 degreesC to 35 degreesC, the PNIPAM shell shrinks from a thickness of 625 nm to 110 nm and the chain density near the core increases from 7.3 x 10(-3) g/cm(3) to 7.2 x 10(-2) g/cm(3). Using such core-shell particles, we have, for the first time, been able to study dynamics of long chains anchored on a particle in dilute dispersion by laser-light scattering. Our results showed that, besides the translational diffusion of the particle as a whole, there also exists an additional slow relaxation mode that is only observable at larger scattering vectors (q),which are presumably related to internal motions of the shell. In the fully swollen state, the relaxation rate of the slow motion (<Gamma>(slow)) is insensitive to the observation length (1/q); however, its contribution to the scattering intensity (A(slow)) increases as q increases. In the shrunken state, <Gamma>(slow) slightly decreases as q increases. <Gamma>(slow) can be scaled to the shell thickness (<L>(brush)) as <Gamma>(slow) proportional to <L>(alpha)(brush), with alpha = -2.5 +/- 0.2, which is smaller than the predicated value of 3.},
	keywords = {AQUEOUS ATRP, BRUSHES, CONFORMATION, DYNAMICS, GLOBULE TYPE TRANSITIONS, INTERFACE, LAYERS, MODEL, POLY(N-ISOPROPYLACRYLAMIDE), SIMULATION},
	isbn = {1520-6106},
	url = {<Go to ISI>://000225417200015},
	author = {Yang, C. and Kizhakkedathu, J. N. and Brooks, D. E. and Jin, F. and Wu, C.}
}
@article {910,
	title = {Synthesis of well-defined environmentally responsive polymer brushes by aqueous ATRP},
	journal = {Macromolecules},
	volume = {37},
	number = {3},
	year = {2004},
	note = {ISI Document Delivery No.: 771TWTimes Cited: 102Cited Reference Count: 56},
	month = {Feb},
	pages = {734-743},
	type = {Article},
	abstract = {Functionalized anionic polystyrene latex particles with ATRP initiators were synthesized by surfactant-free shell-growth emulsion polymerization of styrene and 2-(2{\textquoteright}-chloropropionato)ethyl acrylate (HEA-Cl). N-Isopropylacrylamide (NIPAM) was polymerized from these particles by surface-initiated aqueous ATRP using PMDETA/CuCl and HMTETA/CuCl catalysts to synthesize poly(N-isopropylacrylamide) (PNIPAM) brushes. The grafted latexes were characterized for molecular weight of the PNIPAM chains, grafting density, and hydrodynamic thickness of the grafted polymer layer. Molecular weights of the grafted PNIPAM chains depended on the monomer concentration, concentration of copper(II) complex, and the presence of external initiator in the reaction medium. M-n of the grafted chains increases with increase in the monomer concentration and decreases with addition of copper(II) complex and external initiator. The HMTETA/CuCl catalyst produces higher molecular weight chains than PMDETA/CuCl. Molecular weights from similar to50 000 to 800 000 with low polydispersities, between 1.25 and 1.4, were achieved. The grafting density of PNIPAM on the surface increases with increasing monomer concentration and decreases with addition of copper(II) catalyst and external initiator. Block copolymerization of N,N-dimethylacrylamide from PNIPAM-grafted latex demonstrated that the chains are terminated with a chlorine atom, and the grafting reactions are taking place by the ATRP mechanism. The hydrodynamic thickness (HT) of the grafted PNIPAM layer scales as DP0.66 (where DP = degree of polymerization) at constant grafting density (chains/nm(2)). The HT values for PNIPAM brushes are sensitive to temperature and salt concentration. Since the transition from extended coil to collapsed structure occurs over a range of temperature and salt concentration, it follows a second-order transition, as predicted by theory. The thickness of the collapsed brush is sensitive to the type of stimulus used to induce the phase transition.},
	keywords = {GLOBULE TYPE TRANSITIONS, INTERFACES, N-DIMETHYLACRYLAMIDE) BRUSHES, PARTICLES, POLY(N, POLY(N-ISOPROPYLACRYLAMIDE), PROTEIN, SILICA, SURFACE-INITIATED POLYMERIZATIONS, TEMPERATURE, TRANSFER RADICAL POLYMERIZATION},
	isbn = {0024-9297},
	url = {<Go to ISI>://000188803000010},
	author = {Kizhakkedathu, J. N. and Norris-Jones, R. and Brooks, D. E.}
}
