title: Effect of Surface Charge on Surface-Initiated Atom Transfer Radical Polymerization from Cellulose Nanocrystals in Aqueous Media.
abstract: Cellulose nanocrystals (CNCs) with different charge densities were utilized to examine the role of electrostatic interactions on surface-initiated atom transfer radical polymerization (SI-ATRP) in aqueous media. To this end, growth of hydrophilic uncharged poly(N,N-dimethylacrylamide) (PDMAM) brushes was monitored by electrophoresis, (1)H NMR spectroscopy, and dynamic light scattering (DLS). Molecular weight and polydispersity of PDMAM brushes was determined by GPC analysis of hydrolytically cleaved polymers. Initiator and polymer brush grafting densities, and thus, initiator efficiencies were derived from elemental analysis. Higher initiator efficiency of polymer brush growth was observed for CNCs with higher anionic surface sulfate half-ester group density, but at the expense of high polydispersity caused by inefficient deactivation. PDMAM grafts with number-average molecular weights up to 530 kDa and polydispersity indices <1.5 were obtained under highly diluted monomer concentrations. The role of surface chemistry on the growth of neutral polymer brushes from CNCs in water is emphasized and a model of the interfacial region at the onset of polymerization is proposed. The results presented here could have implications for other substrates that present surface charges and for the assumption that the kinetics of Cu-mediated SI-CRP are analogous to those conducted in solution.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL) Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques , Laboratoire des Polymères STI - IMX - LP, MXD 036 (Bâtiment MXD) Station 12, CH-1015 Lausanne, Switzerland.
authors.forename: Justin O
authors.initials: JO
authors.lastname: Zoppe
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL) Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques , Laboratoire des Polymères STI - IMX - LP, MXD 036 (Bâtiment MXD) Station 12, CH-1015 Lausanne, Switzerland.
authors.forename: Xingyu
authors.initials: X
authors.lastname: Xu
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL) Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques , Laboratoire des Polymères STI - IMX - LP, MXD 036 (Bâtiment MXD) Station 12, CH-1015 Lausanne, Switzerland.
authors.forename: Cindy
authors.initials: C
authors.lastname: Känel
authors.affiliation: EMPA, Swiss Federal Laboratories for Materials Science and Technology , Laboratory of Applied Wood Materials, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
authors.forename: Paola
authors.initials: P
authors.lastname: Orsolini
authors.affiliation: EMPA, Swiss Federal Laboratories for Materials Science and Technology , Laboratory of Applied Wood Materials, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Siqueira
authors.affiliation: EMPA, Swiss Federal Laboratories for Materials Science and Technology , Laboratory of Applied Wood Materials, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Tingaut
authors.affiliation: EMPA, Swiss Federal Laboratories for Materials Science and Technology , Laboratory of Applied Wood Materials, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
authors.forename: Tanja
authors.initials: T
authors.lastname: Zimmermann
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL) Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques , Laboratoire des Polymères STI - IMX - LP, MXD 036 (Bâtiment MXD) Station 12, CH-1015 Lausanne, Switzerland.
authors.forename: Harm-Anton
authors.initials: HA
authors.lastname: Klok
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D055672:Static Electricity; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000178:Acrylamides; D011108:Polymers; C429790:poly(N,N-dimethylacrylamide); D014867:Water; D002482:Cellulose