Copper–poly(tetrafluoroethylene) (PTFE) and gold–PTFE laminates were prepared by surface graft copolymerization of glycidyl methacrylate (GMA) on argon plasma-pretreated PTFE films at an elevated temperature with simultaneous lamination to copper foils or gold substrates. The plasma pretreatment introduces peroxides, which are thermally degraded into radicals to initiate the graft copolymerization of GMA on the PTFE surface. Before lamination, the gold surface was pretreated with alkanethiols to form self-assembled monolayers and then subjected to an Ar plasma treatment. The modified surfaces and interfaces were characterized by x-ray photoelectron spectroscopy and the adhesion strength was assessed by the T-peel test method. By this technique, the Cu–PTFE or Au–PTFE laminates exhibit significantly improved adhesion strengths and the joints are delaminated by cohesive failure inside the bulk of the PTFE film.

To obtain polymer surfaces having different zeta potentials, a poly(ethylene terephthalate) (PET) film surface was graft-poly-merized with an anionic monomer, acrylic acid (AAc) , and a cationic monomer, N,N-dimethylaminoethyl methacrylate (DMA EMA) . In addition, a cellulose film was surface-modified with Chloroacetic acid to introduce anionic carboxyl groups and N,N-dimethylaminopropyl acrylamide (DMAPAA) to introduce cat-ionic dimethylamino groups. Through these surface modifications we could obtain films having zeta potentials ranging from /39 to -58 mV. Adhesive interaction in water between two surfaces of these films was measured with a tensile testing method after lapping the two surfaces in water. When one film was surface-grafted with cationic polymer chains, it exhibited significant adhesion instantaneously in water toward the other surface with a negative zeta potential, such as the surface-modified cellulose films, quartz, and the unmodified PET film. The quartz surface showed a detectable attractive force toward the cationic cellulose surface, but the force was weaker than that toward the cationically grafted surface. Apparently, no correlation was found between the zeta potential of the surfaces and their adhesive strength.

To study the electrostatic interaction between two ionic polymer grafted surfaces in aqueous media, an atomic force microscopic tip surface was modified by graft polymerization of a cationic monomer, dimethylaminoethyl methacrylate (DMAEMA), after being coated with a thin layer of cyanoacrylate polymer. A poly(ethylene terephthalate) (PET) film which was the countersurface of the modified tip for the measurement of atomic force microscopy was also modified by surface graft polymerization of DMAEMA and an anionic monomer, acrylic acid (AAc) . An appreciable adhesive force was observed in water between the DMAEMA-grafted tip and the AAc grafted PET surface, while a repulsive interaction was noticed between the DMAEMA-grafted tip and the DMAEMA-grafted PET film. Addition of KCl to the medium for the atomic force measurement exhibited a remarkable reduction in the adhesive interaction. These interactions were attributed to the Coulombic force between the grafted ionic polymer chains.

Modification of argon plasma-pretreated single-crystal silicon wafer surface via UV-induced graft polymerization with various functional monomers, such as acrylamide (AAm), N,N- diamethylaminoethyl methacrylate (DMAEMA), and 2,2,2-trifluoroethyl acrylate (TFEA), was achieved. The modified Si(100) surfaces were characterized by X-ray photoelectron spectroscopy (XPS), imaging XPS, atomic force microscopy (AFM), and water contact angle measurements. The graft polymerization was affected by plasma pretreatment time and UV irradiation time. XPS results suggest that mild and brief plasma treatment is sufficient to cause surface oxidation and to generate sufficient peroxides and hydroxyl peroxides for the subsequent UV-induced graft polymerization in the presence of a vinyl monomer. Prolonged plasma treatment and the accompanying overoxidation of the silicon surface have an adverse effect on the graft polymerization. For all the cases investigated, the XPS results revealed that the grafted polymers form a thin layer with a thickness of 5 nm or less on the silicon surface. The AAm and TFEA graft-polymerized surfaces were uniform in morphology. However the DMAEMA graft-polymerized surface exhibited structural domains. Contact angle measurements further indicated that the silicon surface could be selectively made hydrophilic or hydrophobic through the proper choice of monomers used for graft polymerization.

Delivery of oligonucleotide to specific cells and maintenance of its biological function are important for nucleic acid therapy. The objective of this paper is to demonstrate that galactosylated low molecular weight chitosan (gal-LMWC) is a safe and effective vector of antisense oligonucleotide (ASO) and plasmid DNA for the hepatocyte targeting delivery. Gal-LMWC has been successfully prepared and MTT cytotoxic assay shows that cytotoxicity of gal-LMWC is lower than that of high molecular weight chitosan (HMWC) and low molecular weight chitosan (LMWC) in HepG2 cells. Using a complex coacervation process, gal-LMWC can form stable nano-complexes with plasmid DNA or with ASO by the electrostatic interaction. The morphometrics, particle size, and the zeta potential of gal-LMWC/ASO complexes and gal-LMWC/plasmid DNA complexes are very similar. The transfection efficiency by using gal-LMWC vector is significantly higher than that of naked DNA or naked ASO in HepG2 cells. Transfection efficiency of gal-LMWC/ASO complexes and gal-LMWC/plasmid DNA complexes depends on the molar ratio of the positive chitosan amino group and the negative DNA phosphate group (N/P ratio) strongly. Inhibition experiments confirm that the enhanced transfection efficiency is due to the ASGR mediated endocytosis of the gal-LMWC/ASO complexes or gal-LMWC/DNA complexes. These results suggest that gal-LMWC can be used in gene therapy to improve the transfection efficiency in vitro and in vivo.