Authors Uhlmann, P. ; Skorupa, S. ; Werner, C. ; Grundke, K.
Title Characterization of Maleic Acid/Anhydride Copolymer Films by Low-Rate Dynamic Liquid-Fluid Contact Angle Measurements Using Axisymmetric Drop Shape Analysis
Date 30.06.2005
Number 12976
Abstract Thin films of alternating maleic acid/anhydride copolymers (poly(octadecene-<I>alt</I>-maleic acid/anhydride),POMA; poly(propene-<I>alt</I>-maleic acid/anhydride), PPMA; poly(styrene-<I>alt</I>-maleic acid/anhydride), PSMA)were studied to unravel the influence of the comonomer characteristics in the backbone on the surface-energetic properties of the copolymer films in the dry state and in contact with aqueous solutions. Watercontact angle measurements revealed a graduation of the wettability of the dry hydrolyzed and annealedcopolymer films that was dependent on the comonomer unit. It ranged from moderately hydrophilic (PPMA,annealed <IMG SRC="/images/gifchars/gamma.gif" BORDER=0 ><SUB>sv</SUB> = 39.9 mJ/m<SUP>2</SUP>) to very hydrophobic (POMA, annealed, <IMG SRC="/images/gifchars/gamma.gif" BORDER=0 ><SUB>sv</SUB> = 18.4 mJ/m<SUP>2</SUP>) surfaces. Liquid-fluid contact angle measurements using captive air bubbles were performed in different aqueous media(pure water, phosphate-buffered saline, and 10<SUP>-</SUP><SUP>3</SUP> M KCl of two different pH values (pH = 3 and pH = 10)to study the copolymer films in their hydrated states relevant for biointerfacial phenomena. It was foundthat the graduation of the wettability of the copolymer films in the dry state is overall maintained uponimmersion in aqueous solutions. The dependence of the wettability on the pH value of the aqueous mediumcould be related to the (de)protonation of the carboxylic groups.
Publisher Langmuir
Citation Langmuir 21 (2005) 6302-6307
Tags acid-base behavior dissociation behavior poly(maleic acid) ionization surface polyethylene monolayers titration polymers tensions

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