The individual and combined adsorption behavior of polyamides and two different silanes to multicomponent glass surfaces was probed with a combination of x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and static contact angle measurements. Samples were analyzed with and without solvent rinsing to separate the weakly bound (physisorbed) and more strongly bound (chemisorbed) species. High-resolution XPS on N Is revealed that the polyamides adsorb to the glass surfaces via protonated amine species at the acidic (OH) sites on the glass surface. Angle-resolved XPS confirmed this by showing that the alkyl portion of the polymer is oriented away from the glass interface. In competitive coadsorption studies it was found that amino-terminated silanes preferentially adsorb to the glass surface, relegating the polyamide to a physisorbed outer layer. When mercaptoterminated silanes were competitively coadsorbed the polyamide was preferentially adsorbed even when present at a concentration twenty times less than that of the silane. Altogether, this work reveals the strong interaction between surface silanols and amino-functionalized organics.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry