title: Arrangements of cationic starch of varying hydrophobicity on hydrophilic and hydrophobic surfaces.
abstract: Arrangements of cationic starches hydrophobized by acetylation (CS-acet) deposited from aqueous electrolyte solutions onto hydrophilized and hydrophobized silica surfaces were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The influence of electrolyte composition, acetylation degree of cationic starch (DS(ACET)), and deposition method was examined. On a hydrophobic substrate, CS-acet formed an open film with structure strongly dependent on DS(ACET) and electrolyte composition of the solution. On a hydrophilic substrate, acetylation increased the hydrophobicity of the film when the starch was deposited by adsorbing. When deposition was made by spin coating, i.e., the CS-acet was forced onto the substrate, the hydrophobic tuning by acetylation was lost. The films deposited by spin coating were thicker and considerably rougher than those deposited by adsorbing.
authors.affiliation: Laboratory of Forest Products Chemistry, Helsinki University of Technology, P.O. Box 6300, FIN-02015 TKK, Finland. katri.kontturi@tkk.fi
authors.forename: Katri S
authors.initials: KS
authors.lastname: Kontturi
authors.forename: Susanna
authors.initials: S
authors.lastname: Holappa
authors.forename: Eero
authors.initials: E
authors.lastname: Kontturi
authors.forename: Leena-Sisko
authors.initials: LS
authors.lastname: Johansson
authors.forename: Sari
authors.initials: S
authors.lastname: Hyvärinen
authors.forename: Soili
authors.initials: S
authors.lastname: Peltonen
authors.forename: Janne
authors.initials: J
authors.lastname: Laine
mesh_terms: D000107:Acetylation; D002412:Cations / Q000737:chemistry; D004573:Electrolytes / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D012822:Silicon Dioxide / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D013213:Starch / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D002412:Cations; D004573:Electrolytes; D012822:Silicon Dioxide; D013213:Starch