Formation of amorphous carbon on the surface of poly(ethylene terephthalate) by helium plasma based ion implantation

The surface modification of poly(ethylene terephthalate) (PET) by helium plasma based ion implantation (He PBII) was studied. The effect of the main process parameters (acceleration voltage, fluence and fluence rate) on the alterations of the surface chemical composition and structure were investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.According to SRIM calculations, at ion energies above 2 keV the stopping power of PET for He⁺ ions is dominated by the electronic component and the contribution of the nuclear component is relatively small. Degradation of the ester group and carbonisation were observed by XPS due to elimination of O-rich fragments. The total C-content of the modified layer increased with the increase of fluence rate and acceleration voltage of particles, enabling the purposeful alteration of the surface composition. A strong broadening was detected in the Raman spectrum between 1000 and 1700 cm⁻¹, testifying to the intense formation of amorphous carbon. The area ratio of the D (∼1410 cm⁻¹) to G (∼1570 cm⁻¹) band increased with the increase of particle fluence and the increase of acceleration voltage, offering the possibility of tailoring the chemical structure of the amorphous carbon layer created by the He PBII treatment.     

Hydrophobic coating of surfaces by plasma polymerization in an RF plasma reactor with an outer planar electrode: synthesis,characterization and biocompatibility

This paper presents the plasma polymerization of poly(hexafluorobutyl acrylate)(PHFBA) thin films on different substrates in an RF plasma reactor with an outer planar electrode. This reactor configuration allows?large area uniformity and fast processing times. Deposition rates of up to60 nm min-1were observed. The influence?of plasma power and substrate temperature on the?deposition rate, structure and wettability of the as-deposited films was?investigated. It was observed that better hydrophobicity was obtained at high plasma power and in low temperature conditions. PHFBA thin films deposited on electrospun poly(acrylonitrile) fiber mats under such conditions resulted in superhydrophobic surfaces with?contact angle values greater than 150°.In?vitro cell studies using human epithelial cells demonstrated the non-toxic nature of the?plasma-polymerized PHFBA films.     

Fabrication of a polymer with three-dimensional structure by the ion beam graft polymerization method

The graft polymerization method is one of the most effective techniques to produce a new polymer with unique function. To produce the polymer, we conducted experiments on radiation graft polymerization using ion beams of several hundred keV energy. A high density polyethylene (PE) film was irradiated with H⁺ beams, then, graft polymerization with monomer solution such as acrylic acid or acrylonitrile was conducted. Radicals generated by the interaction between the beam ions and the PE molecules become the starting point of the graft polymerization. Since the range in PE depends on ion energy, the density distribution of the graft chain can be controlled by the ion energy. Using a mask which restricts the ion beam incidence, PE sheets containing graft chains only in the unmasked area were obtained. Multiple ion beam graft polymerization can produce a polymer which has some functional bases at specified position. We have demonstrated the production of a polymer film with a three-dimensional structure.     

Preparation of ion-track membranes of poly(p-phenylene terephthalamide): Control of pore shape by irradiation with different ion beams

The preparation of ion-track membranes of thermally stable poly(p-phenylene terephthalamide) (PPTA) was performed by ion beam irradiation followed by chemical etching with a sodium hypochlorite solution. Cylindrical pores were observed in the membrane irradiated with ¹⁹⁷Au and ²³⁸U ions at an energy of 11.1 MeV/n. In contrast, funnel shape pores appeared in the membrane irradiated with ⁸⁴Kr, ¹⁰²Ru and ¹²⁹Xe ion at energies of 6.2, 3.6 and 3.5 MeV/n, respectively. The ¹⁹⁷Au and ²³⁸U ion irradiation was found to exhibit more than four times larger sensitivity to the track etching under the same etching conditions. Consequently, the pore shape can be controlled by the masses and energies of the irradiated ions, in close relation to the etching sensitivity of the track.