title: Experimental design and analysis of activators regenerated by electron transfer-atom transfer radical polymerization experimental conditions for grafting sodium styrene sulfonate from titanium substrates.
abstract: A 24factorial design was used to optimize the activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) grafting of sodium styrene sulfonate (NaSS) films from trichlorosilane/10-undecen-1-yl 2-bromo-2-methylpropionate (ester ClSi) functionalized titanium substrates. The process variables explored were: (1) ATRP initiator surface functionalization reaction time; (2) grafting reaction time; (3) CuBr2concentration; and (4) reducing agent (vitamin C) concentration. All samples were characterized using x-ray photoelectron spectroscopy (XPS). Two statistical methods were used to analyze the results: (1) analysis of variance with [Formula: see text], using average [Formula: see text] XPS atomic percent as the response; and (2) principal component analysis using a peak list compiled from all the XPS composition results. Through this analysis combined with follow-up studies, the following conclusions are reached: (1) ATRP-initiator surface functionalization reaction times have no discernable effect on NaSS film quality; (2) minimum (≤24 h for this system) grafting reaction times should be used on titanium substrates since NaSS film quality decreased and variability increased with increasing reaction times; (3) minimum (≤0.5 mg cm-2for this system) CuBr2concentrations should be used to graft thicker NaSS films; and (4) no deleterious effects were detected with increasing vitamin C concentration.
authors.affiliation: Department of Chemical Engineering, University of Washington-Seattle, and National ESCA and Surface Analysis Center for Biomedical Problems , Seattle, Washington 98195.
authors.forename: Rami N
authors.initials: RN
authors.lastname: Foster
authors.affiliation: Department of Bioengineering, University of Washington-Seattle, and National ESCA and Surface Analysis Center for Biomedical Problems , Seattle, Washington 98195.
authors.forename: Patrik K
authors.initials: PK
authors.lastname: Johansson
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University , Pittsburg, Pennsylvania 15213.
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Tom
authors.affiliation: Department of Bioengineering, University of Washington-Seattle, and National ESCA and Surface Analysis Center for Biomedical Problems , Seattle, Washington 98195.
authors.forename: Patrick
authors.initials: P
authors.lastname: Koelsch
authors.affiliation: Departments of Chemical Engineering and Bioengineering, University of Washington-Seattle, and National ESCA and Surface Analysis Center for Biomedical Problems , Seattle, Washington 98195.
authors.forename: David G
authors.initials: DG
authors.lastname: Castner