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  • Zeta potential of photochemically modified polymer surfaces [Elektronski vir]
    Temmel, Susanne ; Kern, Wolfgang ; Luxbacher, Thomas
    The present work is focused on the introduction of sulfonic acid groups (-SO 3 H) onto low-density polyethylene (LDPE) surfaces by photosulfonation. The generation of sulfonic acid groups at the ... polyethylene surfaces and the degree of photosulfonation were examined by FTIR-spectroscopy, contact angle testing as well as zeta potential measurements. The contact angle 0 of water decreased from 0=-99° (pristine LDPE) to about 0=-30° (photosulfonated LDPE) and then remained constant. From contact angle data with different test liquids a significant increase in the polar component gama P of the surface tension was evidenced, while the dispersive component gama D remained almost constant. Zeta potential measurements were performed for the investigation of electrokinetic effects at the solid/liquid interface. The %-potential of the modified LDPE surfaces shifted to less negative values with increasing UV irradiation time corresponding to a higher hydrophilicity of the photosulfonated polyethylene surfaces. Concomitantly the isoelectric point was shifted to lower pH values, which indicates an increasing amount of acidic -SO3H groups present at the sample surface. However, strongly photosulfonated LDPE surfaces became partly soluble in aqueous media which limits the amount of -SO3H groups present at the modified LDPE surface. To reduce these effects, LDPE samples were cross-linked by e-beam irradiation and then subjected to the photosulfonation process. Compared to standard LDPE, crosslinked LDPE displayed a higher content of -SO3H groups and higher surface polarity after photosulfonation. This was evidenced both by zeta potential and contact angle measurements. It is thus demonstrated that sample pre-treatment by crosslinking provides more stable surfaces which maintain their polar properties during water contact. This is explained by a lower amount of extractable components as a result of radiation-induced network formation.
    Vir: Characterization of Polymer Surfaces and Thin Films [Elektronski vir] (Vol. 132, 2006, str. 54-61)
    Vrsta gradiva - prispevek na konferenci ; neleposlovje za odrasle
    Leto - 2006
    Jezik - angleški
    COBISS.SI-ID - 96767233
    DOI

Vnos na polico