@article {2426, title = {Products and kinetics of the reactions of an alkane monolayer and a terminal alkene monolayer with NO3 radicals}, journal = {Journal of Geophysical Research-Atmospheres}, volume = {114}, year = {2009}, note = {ISI Document Delivery No.: 401ZETimes Cited: 10Cited Reference Count: 95Gross, Simone Bertram, Allan K.}, month = {Jan}, pages = {14}, type = {Article}, abstract = {The reactions of an alkanethiol and a terminal alkenethiol self-assembled monolayer with NO3 radicals (in the presence of NO2 and O-2) were studied. For the alkane monolayer, infrared (IR) spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS) confirmed the formation of organonitrates (RONO2). The observation of organonitrates is in contrast to the recent X-ray photoelectron spectroscopy (XPS) data, which showed very little nitrogen-containing surface species. The identification of organonitrates may help explain why significant volatilization of the organic chain was not observed in recent studies of alkane monolayer oxidation by NO3 radicals. The reactive uptake coefficient (gamma) of NO3 on alkene monolayers determined in our study is higher than the values obtained in a recent study using liquid and solid alkene bulk films. A possible reason for this difference may be the location of the double bond at the interface. Using the g value determined in our studies, we show that under conditions where NO3 is high the lifetime of an alkene monolayer in the atmosphere may be short ( approximately 20 min). XPS, IR, and ToF-SIMS were used to identify surface functional groups after the oxidation of the alkene monolayers by NO3. The results are consistent with the formation of C-O, aldehyde/ketone, carboxylic groups, and nitrogen containing species.}, keywords = {GAS-PHASE, HETEROGENEOUS OXIDATION, ION, MASS-SPECTROMETRY, NITROGEN-DIOXIDE, OH RADICALS, OLEIC-ACID, POLYCYCLIC AROMATIC-HYDROCARBONS, REACTIONS, RELATIVE RATE CONSTANTS, SELF-ASSEMBLED MONOLAYERS, VOLATILE ORGANIC-COMPOUNDS}, isbn = {0148-0227}, url = {://000262982300003}, author = {Gross, S. and Bertram, A. K.} } @article {2697, title = {Surface Modification of Polyvinyl Chloride Sheets via Growth of Hydrophilic Polymer Brushes}, journal = {Macromolecules}, volume = {42}, number = {9}, year = {2009}, note = {ISI Document Delivery No.: 441PNTimes Cited: 7Cited Reference Count: 65Zou, Yuquan Kizhakkedathu, Jayachandran N. Brooks, Donald E.}, month = {May}, pages = {3258-3268}, type = {Article}, abstract = {Poly(N,N-dimethylacrylamide) (PDMA) brushes were successfully grown from polyvinyl chloride (uPVC) sheets via well-controlled surface-initiated atom transfer radical polymerization (SI-ATRP). An ATRP initiator containing a chloropropionate moiety was chemically tethered onto the surface of PVC via it novel wet chemical modification. Negatively charged sulfate groups were introduced to facilitate polymerization. By incorporating a chemically cleavable group into the initiator, molecular weight, polydispersity and graft density of a series of PDMA brushes synthesized on the flat surface were unambiguously characterized for the first time by gel permeation chromatography. ATR-FTIR, contact angle, SEM and AFM were used to characterize the PDMA grafted surfaces. Reaction conditions Such as monomer concentration, reaction time, copper(II) concentration and salt additives were varied to systematically investigate their effects on molecular weight and graft density of the PDMA grafted from PVC. Molecular weights of grafted PDMA brushes varied from ca. 20 000 to 2 170 000 Da, while craft density ranged from 0.08 to 1.13 chains/nm(2). Polydispersity of grafted PDMA brushes was controlled between 1.20 and 1.60 by Cu(II) complex addition. Kinetic studies revealed that the surface initiation was a slow process and graft density increased during the reaction. The brush uniformity increased with increasing reaction time. Reinitiation of the obtained PDMA brushes was demonstrated, suggesting that the polymerization is "living". The successful growth of a PDMA-b-poly(N-isopropylacrylamide) (PNIPAM) copolymer brush was verified by GPC and AFM.}, keywords = {AQUEOUS ATRP, ATOMIC-FORCE MICROSCOPY, CARBON NANOTUBES, COPOLYMER BRUSHES, density, GLYCOL), GRAFT, PLASMA-PROTEIN ADSORPTION, POLY(ETHYLENE, SELF-ASSEMBLED MONOLAYERS, SERUM-ALBUMIN, TRANSFER RADICAL POLYMERIZATION}, isbn = {0024-9297}, url = {://000265781300007}, author = {Zou, Y. Q. and Kizhakkedathu, J. N. and Brooks, D. E.} } @article {2499, title = {Surface-enhanced IR-visible sum frequency generation vibrational spectroscopy}, journal = {Physical Chemistry Chemical Physics}, volume = {11}, number = {18}, year = {2009}, note = {ISI Document Delivery No.: 436KPTimes Cited: 2Cited Reference Count: 79Li, Qifeng Kuo, Chiung Wen Yang, Zheng Chen, Peilin Chou, Keng C.}, pages = {3436-3442}, type = {Article}, abstract = {Surface-enhanced IR-visible sum frequency generation (SFG) was studied using Ag and Au films over nanospheres (AgFON and AuFON), which provided large area of reproducible nanoscale structures with well-defined morphology. SFG vibrational spectra for a self-assembled monolayer of octadecanethiol were investigated on spheres with diameters ranging from 300 nm to 620 nm. With an input wavelength of 532 nm, a sphere diameter near 360 nm produced the maximum enhancement, which was consistent with the localized surface-plasmon resonant wavelength identified by minimum reflectivity. The measured second-order susceptibility for the asymmetric CH3 stretch mode of octadecanethiol was enhanced by up to 27 times on AgFON, which corresponded to an SFG enhancement factor of similar to 730. The SFG enhancement factor for AuFON was a quarter of that from AgFON. The SFG enhancement factor for the symmetric CH3 mode was about 10 times smaller than that for the asymmetric CH3 mode. This difference can be explained by the highly directional electrical-field parallel to the surface, created at the junction between nanospheres. Polarization-dependent studies also indicated that excitations with the electrical field parallel to the surface was the main contribution to the observed surface enhancements, and the electrical field perpendicular to the surface offered little enhancement.}, keywords = {2ND-HARMONIC GENERATION, METAL NANOPARTICLES, NANOPARTICLES, NANOSPHERE, platinum, RAMAN-SCATTERING SERS, RHODAMINE 6G MOLECULES, SELF-ASSEMBLED MONOLAYERS, SILVER ELECTRODE, SPECTRA, SUPPORTED PD NANOPARTICLES, SURFACES, TOTAL-REFLECTION}, isbn = {1463-9076}, url = {://000265413300011}, author = {Li, Q. F. and Kuo, C. W. and Yang, Z. and Chen, P. L. and Chou, K. C.} } @article {894, title = {Plasma protein adsorption to surfaces grafted with dense homopolymer and copolymer brushes containing poly(N-isopropylacrylamide)}, journal = {Journal of Biomaterials Science-Polymer Edition}, volume = {15}, number = {9}, year = {2004}, note = {ISI Document Delivery No.: 865ALTimes Cited: 13Cited Reference Count: 38Symposium on Gels, Genes, Grafts and Giants held in Celebration of the 70th Birthday of Allan HoffmanDEC, 2002Maui, HIUniv Washington Engineered Biomat NSF Engn Res Ctr}, pages = {1121-1135}, type = {Proceedings Paper}, abstract = {Growing polymer chains from surface initiators in principle allows much more dense polymer surface layers to be created than can be produced by grafting of whole (self-excluding) chains. We have utilized aqueous atom transfer radical polymerization to graft a series of cleavable hydrophilic poly (N-isopropylacrylamide) (PNIPAM) homopolymers and block copolymers of substituted acry-lamides from polystyrene latex to give brushes of controlled MW and surface density. Average chain separations much less than their free solution radii of gyration have been achieved. Exposure to radiolabeled single proteins or to whole plasma and subsequent analysis by SDS-PAGE shows that PNIPAM brushes decrease protein adsorption relative to the latex surface or other substituted polyacrylamides. The PNIPAM brushes exhibit a second-order phase transition around 30degreesC as reflected by a decrease in the hydrodynamic thickness of the brush at higher temperatures. Total plasma protein adsorption is increased at 40degreesC compared to 20degreesC but there is significant differential adsorption behavior among the proteins detected by gel-electrophoresis analysis.}, keywords = {ADSORPTION, BIOMATERIALS, block copolymer, CHROMATOGRAPHY, FIBRINOGEN ADSORPTION, grafted latex, I-125 radiolabel, MODEL, OXIDE), plasma protein, POLY(ETHYLENE GLYCOL), POLY(N-ISOPROPYLACRYLAMIDE), polymer brush, POLYMER BRUSHES, PREVENTION, SDS-PAGE, SELF-ASSEMBLED MONOLAYERS, SERUM-ALBUMIN ADSORPTION}, isbn = {0920-5063}, url = {://000224674600005}, author = {Janzen, J. and Le, Y. and Kizhakkedathu, J. N. and Brooks, D. E.} } @article {909, title = {Synthesis and characterization of well-defined hydrophilic block copolymer brushes by aqueous ATRP}, journal = {Polymer}, volume = {45}, number = {22}, year = {2004}, note = {ISI Document Delivery No.: 862NOTimes Cited: 27Cited Reference Count: 79}, month = {Oct}, pages = {7471-7489}, type = {Article}, abstract = {Homopolymer brushes of poly(N,N-dimethylacrylamide) (PDMA), poly(methoxyethylacrylamide) (PMEA) and poly(N-isopropylacrylamide)(PNIPAM) grown on atom transfer radical polymerization (ATRP) initiator functionalized latex particles were used as macroinitiators for the synthesis of PDMA-b-PNIPAM/PMEA, PMEA-b-PDMA/PNIPAM and PNIPAM-b-PDMA block copolymer brushes by surface initiated aqueous ATRP. The grafted homopolymer and block copolymer brushes were analyzed for molecular weight, molecular weight distribution, chain grafting density, composition and hydrodynamic thickness (HT) using gel permeation chromatography-multi-angle laser light scattering, H-1 NMR, particle size analysis and atomic force microscopy (AFM) techniques. The measured graft molecular weight increased following the second ATRP reaction in all cases, indicating the second block had been added. Chain growth depended on the nature of the monomer used for block copolymerization and its concentration. Unimodal distribution of polymer chains in GPC with non-overlap of molar mass-elution volume curves implied an efficient block copolymerization. This was supported by the increase in HT measured by particle size analysis, equilibrium thickness observed by AFM and the composition of the block copolymer layer by H-1 NMR analysis, both in situ and on cleaved chains in solution. 1H NMR analysis of the grafted latex and cleaved polymers from the surface demonstrated that accurate determination of the copolymer composition by this method is possible without detaching polymer chains from surface. Block copolymer brushes obey the same power law dependence of HT on molecular weight as homopolymer brushes in good solvent conditions. The NIPAM-containing block copolymer brushes were sensitive to changes in the environment as shown by a decrease in HT with increase in the temperature of the medium. (C) 2004 Elsevier Ltd. All rights reserved.}, keywords = {AMBIENT-TEMPERATURE, aqueous atom transfer radical polymerization, ATOMIC-FORCE MICROSCOPY, BRUSHES, CONTROLLED GROWTH, hydrophilic diblock copolymers, LIGHT-SCATTERING, METHYL-METHACRYLATE, N-DIMETHYLACRYLAMIDE), POLY(N, POLYELECTROLYTE BRUSHES, POLYMER BRUSHES, SELF-ASSEMBLED MONOLAYERS, SIZE-EXCLUSION CHROMATOGRAPHY, TRANSFER RADICAL POLYMERIZATION}, isbn = {0032-3861}, url = {://000224497900011}, author = {Kizhakkedathu, J. N. and Kumar, K. R. and Goodman, D. and Brooks, D. E.} } @article {653, title = {Synthesis of poly(N,N-dimethylacrylamide) brushes from charged polymeric surfaces by aqueous ATRP: Effect of surface initiator concentration}, journal = {Macromolecules}, volume = {36}, number = {3}, year = {2003}, note = {ISI Document Delivery No.: 643NUTimes Cited: 49Cited Reference Count: 34}, month = {Feb}, pages = {591-598}, type = {Article}, abstract = {We have synthesized polystyrene shell latex (PSL) surfaces with different initiator concentrations by changing the feed ratio of styrene to 2-(methyl-2{\textquoteright}-chloropropionato)ethyl acrylate (HEACl) in a series of shell-growth copolymerization reactions. Surfaces were characterized by conductometric titration of saponified and nonsaponified functionalized PSL to give the surface charge and initiator concentrations accessible to aqueous reagents and by H-1 NMR methods. Poly(N,N-dimethylacrylamide) brushes were grafted from the functionalized surfaces by aqueous atom transfer radical polymerization and the dependence of molecular weight and chain density determined as a function of monomer concentration, ligand type, and surface initiator concentration by analyzing the chains cleaved from the PSL by saponification. M. varies linearly with monomer concentration for most systems, and grafting density is roughly independent of monomer concentration except at the highest initiator concentration. Very high molecular weights were obtained at low initiator concentration, up to M-n similar to 1.2 x 10(6) with M-w/M-n < 1.3; chain separations down to 1.1 mn and brush thicknesses to similar to800 nm were found. Grafting density varies as (initiator surface concentration)(2.6). The surface charge density also varies among the latexes synthesized and seems to play a role in this strong dependence on surface initiator concentration, perhaps by partially immobilizing the positively charged catalyst complex.}, keywords = {ADSORPTION, SELF-ASSEMBLED MONOLAYERS, SUBSTRATE, TRANSFER RADICAL POLYMERIZATION}, isbn = {0024-9297}, url = {://000180868000015}, author = {Kizhakkedathu, J. N. and Brooks, D. E.} } @inbook {654, title = {Synthesis of poly(N,N-dimethylacrylamide) brushes from functionalized latex surfaces by aqueous atom transfer radical polymerization}, booktitle = {Advances in Controlled/Living Radical Polymerization}, series = {Acs Symposium Series}, volume = {854}, year = {2003}, note = {ISI Document Delivery No.: BW85KTimes Cited: 7Cited Reference Count: 30Proceedings Paper224th National Meeting of the American-Chemical-SocietyAUG 17-22, 2002BOSTON, MASSACHUSETTSAmer Chem Soc1155 SIXTEENTH ST NW, WASHINGTON, DC 20036 USA}, pages = {316-330}, publisher = {Amer Chemical Soc}, organization = {Amer Chemical Soc}, address = {Washington}, abstract = {Negatively charged, ATRP initiator functionalized polystyrene latexes were synthesized and N,N-dimethylacrylamide was polymerized from their surfaces by aqueous ATRP using several catalyst combinations. Very high grafting densities and molecular weights were achieved with good polydispersities. The brushes exhibited a strong repulsive force that increased with molecular weight in atomic force microscopy measurements. Hydrodynamic thicknesses were consistent with theory. Polymerization from these surfaces is very different from ATRP in solution and depends on monomer concentration in solution, type of catalyst, and surface initiator concentration. The observations were explained with an electrostatic model of the surface region that predicts an increase in the local concentration of Cu(I) and Cu(II) catalyst complexes.}, keywords = {ADSORPTION, BLOCK-COPOLYMERS, density, FORCE MICROSCOPE, INITIATED POLYMERIZATIONS, LAYER, MEDIA, POLYMERS, SELF-ASSEMBLED MONOLAYERS}, isbn = {0097-61560-8412-3854-5}, url = {://000183406500022}, author = {Kizhakkedathu, J. N. and Goodman, D. and Brooks, D. E.}, editor = {Matyjaszewski, K.} } @article {405, title = {Synthesis and characterization of polymer brushes of poly(N,N-dimethylacrylamide) from polystyrene-latex by aqueous atom transfer radical polymerization}, journal = {Macromolecules}, volume = {35}, number = {11}, year = {2002}, note = {ISI Document Delivery No.: 554GUTimes Cited: 64Cited Reference Count: 51}, month = {May}, pages = {4247-4257}, type = {Article}, abstract = {Negatively charged polystyrene latex was synthesized, and a copolymer shell of 2-(methyl-2{\textquoteright}-chloropropionato)ethyl acrylate (HEA-Cl) and styrene was added, from which poly(N,N-dimethylacrylamide) (PDMA) was polymerized by atom transfer radical polymerization in aqueous suspension at room temperature. Increasing monomer concentration in the presence of CuCl or CuBr and one of three ligands (N,N,N{\textquoteright},N{\textquoteright},N"-pentamethyldiethylenetriamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), and tris [2-(dimethylamino)ethyl] amine (Me6TREN)) produced grafts whose molecular weight increased to over 600 000 and polydispersities in the range of 1.3-1.8, determined from chains recovered following cleavage by base. Hydrodynamic brush thicknesses were 70-800 nm, and average chain separations, calculated from M-n and the mass of polymer recovered per particle, varied from 4.0 to 1.1 nm. Very high grafting densities were achieved with good molecular weight control, the highest densities yet reported for high molecular weight polymer chains grown from a surface. Control of the polymerization was improved by addition of Cu(II) to enhance deactivation of free radicals, by including a low concentration of exogenous hydrophobic initiator at high monomer concentration and by reducing latex concentration. Increasing the concentration of exogenous initiator reduced graft thickness but eliminated control over the polydispersity. The unusual conditions required for optimization of the reaction and the observation of decreasing chain separation as M-n increased were explained by invoking a model of the particle surface that took into account the finite depth and high copolymer concentration of the region in which chains were initiated and particularly the fixed charges due to the sulfate initiator of shell copolymerization.}, keywords = {(METH)ACRYLAMIDES, ADSORPTION, AMBIENT-TEMPERATURE, BLOCK-COPOLYMERS, CARBOCATIONIC, FACILE, POLYELECTROLYTE BRUSHES, POLYMERIZATION, SELF-ASSEMBLED MONOLAYERS, SURFACE, SYNTHESIS, TETHERED CHAINS}, isbn = {0024-9297}, url = {://000175728100006}, author = {Jayachandran, K. N. and Takacs-Cox, A. and Brooks, D. E.} } @article {4577, title = {Carceplexes and hemicarceplexes}, journal = {Chemical Reviews}, volume = {99}, number = {4}, year = {1999}, note = {ISI Document Delivery No.: 189WZTimes Cited: 258Cited Reference Count: 229}, month = {Apr}, pages = {931-967}, type = {Review}, keywords = {CONSTRICTIVE BINDING, CRYSTAL-STRUCTURE, DIELS-ALDER REACTION, ENDOHEDRAL METALLOFULLERENES, ENERGY-TRANSFER, HOST-GUEST COMPLEXATION, HYDROGEN-BONDING PREFERENCES, REVERSIBLE MOLECULAR CAPSULES, SELF-ASSEMBLED MONOLAYERS, supramolecular chemistry, TRIPLET}, isbn = {0009-2665}, url = {://000079930300001}, author = {Jasat, A. and Sherman, J. C.} } @article {4351, title = {Water-soluble cavitands: Synthesis of methylene-bridged resorcin[4]arenes containing hydroxyls and phosphates at their feet and bromomethyls and thiomethyls at their rims}, journal = {Journal of Organic Chemistry}, volume = {63}, number = {20}, year = {1998}, note = {ISI Document Delivery No.: 127ZGTimes Cited: 11Cited Reference Count: 31}, month = {Oct}, pages = {6824-6829}, type = {Article}, abstract = {The synthesis of rim-functionalized methylene-bridged resorcin[4]arenes ("cavitands") containing hydrophilic propanol or water-solublilizing propylphosphate feet is described. The cavitands possess the synthetically useful benzylthiol (cavitands 6 and 16) or benzylbromide (cavitands 9 and 11) functionalities at their rims, which are suitable for further derivatization near the hydrophobic cavity of the cavitand. These water-soluble cavitands represent new building blocks that are ideal for use in aqueous supramolecular chemistry. As an example of their synthetic utility in supramolecular studies, we have reacted phosphate-footed cavitands 11 and 16 with cysteine-containing peptide 17 and chloroacetylated peptide 19, respectively, to afford the corresponding de novo proteins 18 and 20.}, keywords = {ADSORPTION, BUILDING-BLOCKS, CARCERANDS, ENCAPSULATION, HOST-GUEST COMPLEXATION, MOLECULAR, PHASE, RECOGNITION, RESORCINARENES, SELF-ASSEMBLED MONOLAYERS}, isbn = {0022-3263}, url = {://000076380300019}, author = {Mezo, A. R. and Sherman, J. C.} }