@article {867,
	title = {Attractive bridging interactions in dense polymer brushes in good solvent measured by atomic force microscopy},
	journal = {Langmuir},
	volume = {20},
	number = {6},
	year = {2004},
	note = {ISI Document Delivery No.: 802JMTimes Cited: 25Cited Reference Count: 56},
	month = {Mar},
	pages = {2333-2340},
	type = {Article},
	abstract = {Using an atomic force microscope (AFM), we have investigated the interaction forces exerted by latex particles bearing densely grafted polymer brushes consisting of poly(N,N-dimethylacrylamide) (PDMA), poly(methoxyethylacrylamide) (PMEA), poly(N-isopropylacrylamide) (PNIPAM), and PMEA-b-PNIPAM in aqueous media (good solvent). The brushes were prepared by controlled surface-initiated atom transfer radical polymerization, and the hydrodynamic thicknesses were measured by dynamic light scattering. The molecular weight (M-n), grafting density (sigma), and polydispersity (PDI) of the brushes were determined by gel permeation chromatography and multiangle laser light scattering after cleaving the polymer from the latex surface by hydrolysis. Force profiles of PDMA (0.017 nm(-2) less than or equal to sigma less than or equal to 0.17 nm(-2)) and PMEA (sigma = 0.054 nm(-2)) brushes were purely repulsive upon compression, with forces increasing with M-n and sigma, as expected, due to excluded volume interactions. At a sufficiently low grafting density (sigma = 0.012 nm(-2)), PDMA exhibited a long-range exponentially increasing attractive force followed by repulsion upon further compression. The long-range attractive force is believed to be due to bridging between the free chain ends and the AFM tip. The PNIPAM brush exhibited a bridging force at a grafting density of 0.037 nm(-2), a value lower than the sigma needed to induce bridging in the PDMA brush. Bridging was therefore found to depend on grafting density as well as on the nature of the monomer. The grafting densities of these polymers were larger than those typically associated with bridging. Bridging interactions were used to confirm the presence of PNIPAM in a block copolymer PMEA-b-PNIPAMA brush given that the original PMEA homopolymer brush produced a purely repulsive force. The attractive force was first detected in the block copolymer brush at a separation that increased with the length of the PNIPAM block.},
	keywords = {ADSORBED POLYMERS, CHAIN, COPOLYMERS, IONIC-STRENGTH, LAYERS, LIGHT-SCATTERING, MICA, POLYELECTROLYTE, POOR SOLVENT, SURFACE INTERACTION FORCES},
	isbn = {0743-7463},
	url = {<Go to ISI>://000220159800048},
	author = {Goodman, D. and Kizhakkedathu, J. N. and Brooks, D. E.}
}
@article {399,
	title = {Studies of a benzoporphyrin derivative with Pluronics},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {80},
	number = {10},
	year = {2002},
	note = {ISI Document Delivery No.: 623LCTimes Cited: 14Cited Reference Count: 22},
	month = {Oct},
	pages = {1321-1326},
	type = {Article},
	abstract = {The synthetic route for the benzoporphyrin derivatives produces two regioisomers in equimolar quantities (ring A and B isomers). A derivative of the A-ring product, BPD-MA (benzoporphyrin-derivative monoacid ring A, verteporfin), has recently been approved in North America and Europe for the treatment of age-related macular degeneration. The B-ring isomers, contrary to the A-ring isomers, exhibit high aggregation in many formulations, which results in inadequate drug delivery for clinical uses. To avoid aggregation, a non-ionic surfactant polymer such as a Pluronic - poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) - may be used as a formulation excipient. The triblock polymer investigated here is designated P123 (or poloxamer 403). When used to formulate a monoacid benzoporphyrin B-ring derivative (2), a critical micelle concentration of P123 in water occurred at approximately 0.015 to 0.03\%. The apparent pK(a) of compound 2 was dependent on its concentration in P123, and decreased as the molar ratio (P123:2) increased. High concentrations of P123 and neutral pH were found to be the best conditions to maintain the drug in its monomeric form. Kinetic studies suggest that the aggregate of 2 contains several molecules, and is formed by a catalyzed self-assembly process. Samples with 1 mg mL(-1) of drug, at pH = 7.4, and 4.8\% of Pluronic showed satisfactory capacity to load and keep monomers stable. This formulation has potential PDT applications.},
	keywords = {AGGREGATION, AQUEOUS-SOLUTIONS, block copolymers, BPD, COPOLYMERS, DYNAMICS, formulation, micelles, PHOTODYNAMIC THERAPY, photodynamic therapy (PDT), PHOTOSENSITIZERS, photosensitizing drug, Pluronic, poloxamers, porphyrins, SURFACTANTS, THERMODYNAMICS},
	isbn = {0008-4042},
	url = {<Go to ISI>://000179703700007},
	author = {Hioka, N. and Chowdhary, R. K. and Chansarkar, N. and Delmarre, D. and Sternberg, E. and Dolphin, D.}
}
@article {5206,
	title = {XPS study of interfaces in a two-layer light-emitting diode made from PPV and Nafion with ionically exchanged Ru(bpy)(3)(2+)},
	journal = {Applied Surface Science},
	volume = {174},
	number = {1},
	year = {2001},
	note = {ISI Document Delivery No.: 416RQTimes Cited: 13Cited Reference Count: 39},
	month = {Apr},
	pages = {43-50},
	type = {Article},
	abstract = {X-ray photoelectron spectroscopy (XPS) was used to investigate the interfacial chemistries occurring in a prototype two-layer polymer light-emitting diode that had been fabricated from PPV and Nafion with ion-exchanged Ru(bpy)(3)(2 +) Magnesium and indium tin oxide (ITO) were used as electrodes, and XPS observations were made as the different layers were added sequentially. Specifically, Mg was deposited on a layer of Nafion with incorporated Ru(bpy)(3)(2 +), and this was itself deposited on PPV-coated ITO. The morphology of Nafion, which is dictated by the strongly hydrophilic and hydrophobic groups that compose it, is indicated to rearrange with the incorporation of Ru(bpy)(3)(2 +) this rearrangement appears reinforced when a thin film is deposited on PPV. The Mg deposition results in substantial changes in XPS spectra, in part due to a direct interaction with the fluorocarbon backbone of Nation. (C) 2001 Elsevier Science B.V. All rights reserved.},
	keywords = {CHEMISTRY, conjugated polymers, COPOLYMERS, ELECTROLUMINESCENCE, FILMS, luminescence, MEMBRANES, NAFION, POLYETHYLENETEREPHTHALATE, polymer light-emitting diodes, RAY PHOTOELECTRON-SPECTROSCOPY, ruthenium polypyridyl complex, SYSTEMS, X-ray photoelectron spectroscopy},
	isbn = {0169-4332},
	url = {<Go to ISI>://000167794300006},
	author = {Susac, D. and Kono, M. and Wong, K. C. and Mitchell, K. A. R.}
}
