Surface functionalized polyethylene

Materials that typify thermoresponsive behavior are polyethylene—poly (ethylene glycol) copolymers that are used to functionalize the surfaces of polyethylene films (smart surfaces) (20). When the copolymer is immersed in water, the poly(ethylene glycol) functionaUties at the surfaces have solvation behavior similar to poly(ethylene glycol) itself. The abiUty to design a smart surface in these cases is based on the observed behavior of inverse temperature-dependent solubiUty of poly(alkene oxide)s in water. The behavior is used to produce surface-modified polymers that reversibly change their hydrophilicity and solvation with changes in temperatures. Similar behaviors have been observed as a function of changes in pH (21—24). 

Alvarez S, Manolache S, Denes F (2003) Synthesis of polyaniline using horseradish peroxidase immobilized on plasma-functionalized polyethylene surfaces as initiator. J Appl Polym Sci 88(2) 369-379... 

The effect of reactive plasma and its distance form the PE film surface has also been studied in detail [138]. The surface of polyethylene films was modified with various water-soluble polymers [(poly[2-(methacryloy-loxy)ethyl phosphorylcholine] (PMPC), poly[2-(glucosyloxy)ethyl methacrylate] (PGEMA), poly(N-isopropylacrylamide) (PNIPAAm) and poly[N-(2-hy-droxypropyl) methacrylamide] (PHPMA)] using Ar plasma-post polymerisation technique [139]. Here, the reactive sites were generated on the PE surface under the influence of argon plasma. These reactive sites on the surface were then utilised to covalently anchor the functional monomers as shown in Scheme 11. 

Adsorption of block copolymers onto a surface is another pathway for surface functionalization. Block copolymers in solution of selective solvent afford the possibility to both self-assemble and adsorb onto a surface. The adsorption behavior is governed mostly by the interaction between the polymers and the solvent, but also by the size and the conformation of the polymer chains and by the interfacial contact energy of the polymer chains with the substrate [115-119], Indeed, in a selective solvent, one of the blocks is in a good solvent it swells and does not adsorb to the surface while the other block, which is in a poor solvent, will adsorb strongly to the surface to minimize its contact with the solvent. There have been a considerable number of studies dedicated to the adsorption of block copolymers to flat or curved surfaces, including adsorption of poly(/cr/-butylstyrcnc)-ft/od -sodium poly(styrenesulfonate) onto silica surfaces [120], polystyrene-Woc -poly(acrylic acid) onto weak polyelectrolyte multilayer surfaces [121], polyethylene-Wocfc-poly(ethylene oxide) on alkanethiol-patterned gold surfaces [122], or poly(ethylene oxide)-Woc -poly(lactide) onto colloidal polystyrene particles [123],... 

The static contact mode is the simplest mode to use for obtaining basic topographic information of solid surfaces. Figure 5.17 is an image of surface crystalline polyethylene obtained with the contact mode. The contact mode was able to detect the nano-scale roughness of crystalline polyethylene, which is believed to be chain folds of polyethylene. The scale of the topography in Figure 5.17 implies that the primary function of an AFM is not the same as a surface profiler... 

Surface-type supports. Many different materials are used for surface functionalization, including beads made from sintered polyethylene, cellulose fibers (cotton, paper, Sepharose, and LH-20), porous highly cross-linked polystyrene or polymethacrylate, controlled pore glass, and silicas. 

We have also carried out some unpublished studies on the temperature dependence of hydrophobic recovery of plasma treated PDMS. The activation energy of this thermal restructuring process is 44 kJ/mol. This is more than the activation energy of viscous flow of PDMS (15 kJ/mol) 2 but much less than the only similar measurement of which we are aware for a carboxylic acid functionalized polyethylene surface (210 kJ/mol). ... 

Ganapathy, R. et al., Immobilization of papain on cold-plasma functionalized polyethylene and glass surfaces, J. Biomater. Sci. Polym. Ed., 12, 1027, 2001. 

Li Q. Matuana L. M. Surface of Cellulosic Materials Modified with Functionalized Polyethylene Coupling Agents. Jourrud of Applied Polymer Science, vol.88, No.2, (2003), pp. 278-286... 

Clearly, a need exists to develop an optimum polymer/bone interface which will provide a direct, stable, permanent fixation in hard tissue for both present and future polymeric components in orthopaedic prostheses. This need provided a strong incentive to pursue the present study on surface activation and to investigate the development of methods of creating hydroxyapatite-like surfaces on polyethylene, the currently used orthopaedic polymer. The surface activation entailed the selective surface phosphonylation of polymeric films made of polyethylene and nylon-12. Nylon-12 was chosen as a representative heterochain polymer whose chain structure closely resembles polyethylene and yet contains hydrolyzable functionalities similar to those of nylon-6, a widely used biomaterial. To study the biocompatibility of a typical new surface, the current study also involved the interaction of a modified polyethylene film with fibroblasts and hydroxyapatite salt solution. 

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