@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 {7360, title = {HYDROXYPROPYL CELLULOSE POLY(ETHYLENE GLYCOL)-CO-POLY(PROPYLENE GLYCOL) AQUEOUS 2-PHASE SYSTEMS - SYSTEM CHARACTERIZATION AND PARTITION OF CELLS AND PROTEINS}, journal = {Enzyme and Microbial Technology}, volume = {14}, number = {10}, year = {1992}, note = {ISI Document Delivery No.: JP468Times Cited: 16Cited Reference Count: 23}, month = {Oct}, pages = {785-790}, type = {Article}, abstract = {Novel aqueous polymeric two-phase systems are described. These systems are formed by mixing hydroxypropyl cellulose (molecular mass 100,000, trade name Klucel L) with poly(ethylene glycol)-co-poly(propylene glycol) copolymer [molecular mass 6,500, poly(propylene glycol) content 50\% w/w, trade name Pluronic P105], in a saline buffer. The phase diagram was measured and the interfacial tensions, phase separation times, and lower phase viscosities of three phase systems having constant Pluronic P105 concentration but varying in Klucel L concentration were determined. The partition behavior of a representative cell, bacterium, and protein and the affinity ligand-mediated alteration in the partition behavior of a protein from a yeast extract protein mixture were also characterized. The results suggest that Klucel L/Pluronic P105 phase systems may be cost-effective substitutes for, or complements to, existing aqueous polymeric phase systems. The physical characterization and representative partition data reported here should facilitate application of these new systems.}, keywords = {AFFINITY, AQUEOUS 2-PHASE SYSTEMS, BAKERS-YEAST, DEXTRAN, GLUCOSE-6-PHOSPHATE DEHYDROGENASE, GLYCOL)-CO-POLY(PROPYLENE GLYCOL) COPOLYMER, HUMAN ERYTHROCYTE, HYDROXYPROPYL CELLULOSE, PARTITION, POLY(ETHYLENE, polymer, PURIFICATION, SALMONELLA-ENTERIDITIS, TENSION}, isbn = {0141-0229}, url = {://A1992JP46800002}, author = {Skuse, D. R. and Norrisjones, R. and Yalpani, M. and Brooks, D. E.} }