title: Synthesis of lignin nanofibers with ionic-responsive shells: water-expandable lignin-based nanofibrous mats.
abstract: A series of ionic responsive poly(N-isopropylacrylamide) (PNIPAM) surface-modified lignin nanofiber mats were prepared by aqueous surface-initiated atom transfer radical polymerization (SI-ATRP). PNIPAM brushes with various molecular weights, thickness, and grafting densities were immobilized on electrospun lignin nanofiber mats by adjusting initial monomer concentration and surface initiator density. ATR-FTIR, SEM, TGA, XPS, and water contact angle measurements confirmed successful surface modification. Analysis of the PNIPAM-modified lignin nanofiber mats (Lig-PN) found that the lower critical solution temperature (LCST) was similar to that of PNIPAM and demonstrated ionic responsive characteristics. With increasing ionic concentration, the water contact angles of the Lig-PN increased correspondingly. AFM images showed that the PNIPAM on the lignin nanofiber mat surface expanded in water and contracted in 0.5 M Na(2)SO(4).
authors.affiliation: Advanced Biomaterials Chemistry Lab, Faculty of Forestry, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
authors.forename: Guangzheng
authors.initials: G
authors.lastname: Gao
authors.forename: James Ian
authors.initials: JI
authors.lastname: Dallmeyer
authors.forename: John F
authors.initials: JF
authors.lastname: Kadla
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D007477:Ions; D008031:Lignin / Q000737:chemistry*; D057139:Nanofibers; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014867:Water
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D007477:Ions; D011108:Polymers; D014867:Water; C052970:poly-N-isopropylacrylamide; D008031:Lignin