title: Morphological imaging of single methylcellulose chains and their thermoresponsive assembly on a highly oriented pyrolytic graphite surface.
abstract: Individual methylcellulose (MC) chains and their thermoresponsive assembly were successfully visualized on a highly oriented pyrolytic graphite (HOPG) surface by atomic force microscopy (AFM). Momentary contact of a dilute MC solution at 4 degrees C onto the HOPG substrate permitted clear imaging of individual MC chains having a molecular thickness of ca. 0.5 nm and a hexagonal orientation. By increasing the solution temperature from 4 to 80 degrees C, it was possible to bring about significant changes in the MC nanomorphology from stretched molecular chains to disordered massive aggregates. It was presumed that the hydrophobic interaction between the MC chains and the HOPG pi-conjugated system led to the successful visualization of thermally responsive changes in the MC conformations. These results imply that HOPG substrates could be used for clear nanoimaging of cellulosic polymers and other structural polysaccharides.
authors.affiliation: Department of Forest and Forest Products Sciences, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Yokota
authors.forename: Tomotsugu
authors.initials: T
authors.lastname: Ueno
authors.forename: Takuya
authors.initials: T
authors.lastname: Kitaoka
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tatsumi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Wariishi
mesh_terms: D006108:Graphite / Q000032:analysis / Q000737:chemistry*; D006358:Hot Temperature; D008747:Methylcellulose / Q000032:analysis / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D006108:Graphite; D008747:Methylcellulose