title: Cellulose nanocrystal-poly(oligo(ethylene glycol) methacrylate) brushes with tunable LCSTs.
abstract: This paper reports on the synthesis of poly(oligoethylene glycol) methyl ether acrylate (POEGMA) grafted cellulose nanocrystals (CNCs) via surface initiated atom transfer radical polymerization (ATRP). An ATRP initiator (α-Bromoisobutyryl bromide) was covalently bonded to the surface of CNCs, followed by copolymerizing di(ethylene glycol) methyl ether methacrylate (MEO2MA) and oligoethylene glycol methyl ether methacrylate (OEGMA300) monomers from the surface using Cu(I)Br/2,2-dipyridal. Multiple POEGMA-g-CNC systems with varying MEO2MA/OEGMA300 content were synthesized, and they displayed a range of lower critical solution temperatures (LCSTs) in aqueous medium. μDSC endotherms and microstructural analysis indicated the collapse of POEGMA chains, followed by the aggregation of nanoparticles above their LCSTs. Cloud point measurements demonstrated a hysteresis in the heating and cooling of the POEGMA-g-CNC systems. It was found that the LCST of the nanoparticles could be tuned to between 23.8 to 63.8°C by adjusting the OEGMA300 content of the POEGMA brushes.
authors.affiliation: Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Grishkewich
authors.affiliation: Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Seyedeh Parinaz
authors.initials: SP
authors.lastname: Akhlaghi
authors.affiliation: Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Yao
authors.initials: Y
authors.lastname: Zhaoling
authors.affiliation: CelluForce Inc., 625, Président-Kennedy Avenue, Montreal, QC H3A 1K2, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Berry
authors.affiliation: Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada. Electronic address: mkctam@uwaterloo.ca.
authors.forename: Kam C
authors.initials: KC
authors.lastname: Tam
mesh_terms: D002236:Carbohydrate Conformation; D002482:Cellulose / Q000737:chemistry*; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D013696:Temperature
chemical_list: D011109:Polymethacrylic Acids; D011092:Polyethylene Glycols; D002482:Cellulose
keywords: ATRP; Cellulose nanocrystals; Grafting from; Lower critical solution temperature; POEGMA