Radiation-grafted hydrogels for biomaterial applications as studied by the ESCA technique

Abstract

SynopsisElectron spectroscopy for chemical analysis (ESCA) was used to study the surface composition of several radiation-grafted polymers in both the dry and hydrated (frozen at 160'K) states. Poly(2-hydroxyethyl methacrylate) (HEMA) and polyacrylamide, both hydrophilic polymers, were readily detected in the hydrated or dehydrated states when grafted to polyethylene substrates. For silicone rubber substrates, both grafts were observed on the hydrated surface but were significantly decreased in surface concentration upon dehydration. For grafts on a polyester-urethane, acrylamide was not a major constituent of either the dry or hydrated surface, while HEMA appeared to increase in abundance upon drying. The amount of the hydrophobic poly(ethy1 methacrylate) found on the graft surface depended upon the substrate polymer used, but the surface abundance of poly(ethy1 methacrylate) was not affected by drying. These results were considered in terms of polar group orientation, polymer chain mobility, substrate permeability, and the limitations of the ESCA technique. The implications of these results with respect to the use of radiation-grafted hydrophilic polymers for biomedical applications are also discussed.

Synthesis and surface characterization of heparin-immobilized polyetherurethanes

“…. 20 Chemical compositions of the surface-modified PUs, calculated from the ESCA survey scan spectra, are shown in Table IV. The oxygen content (13.94%) of the PU surface was increased by PEO grafting (17.98%), while the nitrogen content (2.75%) was decreased after PEO grafting (1.70%).…”

Surface modification and functionalization of polytetrafluoroethylene films via graft copolymerization

“…Polytetrafluoroethylene (PTFE) film with a thickness of about 0.01 cm and a density of 2.18 g/cm 3 was purchased from Goodfellow Inc. of UK. The film was cleaned by Soxhlet extraction in methanol for about 6 hr before use.…”

“…These new functionalities may include improved surface hydrophilicity [3], hydrophobicity [4], biocompatibility [5], conductivity [6], lubricative properties [7] and adhesive properties [8], just to name a few. Among the many techniques used, surface modification via graft copolymerization appears to be the most versatile in the preparation of polymer surfaces with tailored functionalities [9].…”

Analysis of the oil–water interface by XPS at low temperature

“…[9] Application of LTXPS to a silicone rubber grafted with poly(2-hydroxyethylmethacrylate) (PHEMA) revealed the dynamic character of amphiphilic polymer surfaces. [10,11] The recorded C 1s peak was typical of silicone rubber or PHEMA depending on whether the material was analyzed as such or freeze-dried and maintained at low temperature. In the latter case, the C 1s peak was again typical of silicone rubber when the material was brought back at 25…”