Nylon Surface Modification: 2.Nylon-Supported Composite Films

摘要

We have developed techniques for the introduction of reactive functional groups to nylon surfaces via site-specific reactions targeting at the naturally abundant amide repeating units on the surface.In this report,we describe the fabrication of nylon-supported composite surfaces using the most efficient modification methods we have developed.N-Alkylation with (3-glycidoxypropyl)triethoxysilane (GPTES) in the presence of potassium tert-butoxide (t-BuOK) leads to surfaces with silica-like reactivity.Subsequent chemical vapor deposition using tetrachlorosilane (SiCl_4) and water results in composite films with a thin layer of silica,which was made hydrophobic by reaction with a fluorinated silane reagent.Reduction of the amide groups with borane-THF (BH_3-THF) complex leads to a 69% conversion of surface amides to the corresponding secondary amine groups.Alginate was chosen as the model polyelectrolyte for the introduction of a hydrated surface layer.Because of the strong electrostatic interaction between alginate and the amine-enriched nylon surfaces,the adsorption is fast and concentration-independent (within the concentration range studied).The polysaccharide coats the surface homogeneously,without the formation of large aggregates.The amine surfaces obtained by reduction with BH_3-THF (~(BH_3-THF)nylon-NH) and by alkylation with 2-bromoethylamine hydrobromide (BEA-HBr,~(EBA-HBr)nylon-NH_2) were also used to study gold deposition through electroless plating.Immobilization of a negatively charged metal complex (AuCl_4~-) was achieved through electrostatic interaction.Gold particles disperse preferentially in the bulk of ~(EBA-HBr)nylon-NH_2 films,while they remain confined to the outer surface layer of ~(BH_3-THF)nylon-NH films.