Enhanced Crystallinity of PTFE by Ion Irradiation in a Dense Plasma Focus

Abstract

Nitrogen‐ion beam pulses emitted from a low‐energy (1.45 kJ) Mather‐type plasma focus device are used for the surface modification of PTFE polymer specimens. The specimens, placed at a fixed position, are implanted using different number of pulses. Raman spectroscopy and XRD are employed to probe the structural changes incurred during the ion implantation. Both techniques indicate that the crystalline order in the specimens increases with increasing the irradiation dose. The crystallinity degree of the irradiated specimens, as measured from the XRD data, is found to enhance monotonically from 40% to about 55%. Possible crystallinity enhancement mechanism of irradiated PTFE specimens via chain scission is discussed.

Adhesion of Oral Bacteria to Commercial d-PTFE Membranes: Polymer Microstructure Makes a Difference

“…As shown in Figure 1 b,c, the main diffraction peak, originating from (100) crystal plane, was observed at the similar position for both samples, namely, at 18.13° and 18.05° for PTFE-W and PTFE-B, respectively, indicating hexagonal (phase IV) unit cell with similar lattice parameters (d-spacing was 0.4893 nm and 0.4915 nm, respectively). Two low-intensity peaks at around 31.6° and 36.7° are assigned to (110) and (107) crystal planes, respectively [ 38 , 39 ]. The most pronounced difference between the spectra is the markedly narrower and higher (100) peak of the PTFE-W membrane (intensity = 12,454 vs. 1004 for PTFE-B).…”

Effects of long pulse width and high pulsing frequency on surface superhydrophobicity of polytetrafluoroethylene in quasi-direct-current plasma immersion ion implantation

“…The materials are used commercially in a myriad of applications, especially biomedical ones, because of favorable characteristics such as relative high-temperature stability, excellent chemical resistance, low dielectric constant, high electrical resistance, as well as very low surface free energy and friction coefficient. 5,11 Unfortunately, its low surface free energy and poor adhesion to metals and other materials have hampered wider applications. 4,7 The inherent chemical inertness of PTFE also makes conventional chemical surface modification difficult.…”

Characterization of carbon film by Raman spectroscopy

“…The formation of the hot dense plasma (ion density ∼10 25−26 m −3 , temperature ∼1 keV) is followed by the onset of sausage instabilities, enhancing the induced electric field locally. This enhanced electric field, coupled with the magnetic field, accelerates the ions towards the top of the chamber (0 • direction) and electrons towards the positively charged anode (180 • direction) (15)(16)(17)(18).…”

“…The ion energy spectrum basically follows a dN/dE ∼ E −k law, where N is the number of ions with energy E, and k has a value of ∼3.5 (15)(16)(17)(18). In order to measure the ion emission from DPF a photoconductive GaAs detector facing copper disc with a pinhole of 50 μm diameter is used.…”

“…The plasma focus device has proved useful for a wide range of applications, such as lithography, contact microscopy, X-ray backlighting, and material research (14), because of its simplicity, easy maintenance, and portability. For material processing purposes especially in thin film deposition, the DPF technique gives the advantage of being labor saving, taking less treatment time, and having a significant reduction in energy consumption over the other methods (15)(16)(17)(18).…”