With the rapid development of modern materials science, life science and medical science, the application of biomaterials in the field of clinical medicine has become increasingly widespread. Plasma surface modification technology has become a hot issue in the study of biological materials. Among them, the hydrophobic properties of the reinforced material surface have become a development direction of modern biomedical material design. Polytetrafluoroethylene (PTFE) coated medical devices have been successfully applied in the clinical medical field but in some cases (such as cardiovascular stents, surgical blades, etc.), due to the poor mechanical properties of PTFE or the adhesion to the substrate Solid, limiting its wide range of applications m-fluorinated amorphous carbon film (aC:F) due to excellent biocompatibility, anti-bacterial adhesion, low coefficient of friction, abrasion resistance and good chemical inertness, low surface energy , low dielectric constant, etc. have caused widespread interest. Due to the inherent cross-coupling structure formed between the CC bonds and the hydrophobic Ch-like bond similar to PTFE, such films have become a new type of research hotspot. R.Hauert, Bray et al. t7,8 have carried out their research work in biomedical applications.
Various physical, chemical and radiological methods based on plasma and "sub-injection" theoretical models have been used to prepare fluorinated amorphous carbon films.
For Raman absorption spectra of synthetic films using FCVA technology, it can be seen that Raman plots are shoulder-peak curves, which are typical polymer-like structures. 1. Gaussian fitting of their spectra, the introduction of fluorine from Table 2 makes the D peak and G peak table 2 Raman map Gaussian fitting results of the intensity ratio b / / G gradually increased, the width of the G peak narrowed, while the G peak to the direction of low wave number shift. Because the peak intensity ratio /D//G, the width change of the G peak and the ratio of the Indian 3/Indian 2 are inversely proportional to the CF4 flow rate, the plasma density of the ionized-CFz in the vacuum chamber is also increasing. The intensification of particles on surface cavities, defects, and coarse particles will further promote surface planarization.
3.4 Nano-hardness results and analysis The relationship between the nanoindentation load and penetration depth of CFVA composite films under different CF4 flow rates is high CF4 flux, corresponding to the deeper depth of penetration of the diamond indenter under the same load, and unloading The smaller the resulting elastic recovery, the higher CF4 flow corresponds to the lower hardness of the synthetic film. Raman results show that with the increase of CF4 flow rate, the film structure becomes more disordered and the degree of disorder in the film structure increases, so the hardness value gradually decreases. The hardness values ​​of the corresponding films at the three flow rates in the figure are 18.0, 15.3, respectively. 12.4GPa, far higher than the hardness of PTFE 8GPa. It can be seen that the fluorinated amorphous carbon film synthesized by the pulsed magnetic filter cathode vacuum arc source deposition technology has a high hardness, providing a fundamental guarantee for its application -3.5 The results of nanoscratch measurement and analysis are the relationship between nano-scratch loading and scratch displacement for composite films with different CF4 flow rates. Nano-scratch test was performed using a Berkovich trigonal pyramid indenter. The scratch loading rate was 10 mN/min, the scratch displacement was 0.3 mm, and the maximum load was 40 mN. The lateral (friction) force was calculated from the compliance determined by standard experiments, and then Calculate its friction coefficient, and get the relationship between friction coefficient and loading. When the film begins to peel off, the friction coefficient increases sharply. The load at this time is defined as the critical load of film exfoliation. For example, the critical load of diamond-like carbon film is 33.21mN. The introduction of fluorine element makes the film structure more disordered. The critical load of the film decreases slightly, and decreases to 30.42 and 27.3611 at 2 and 8:11, respectively. The hydrophobicity of the hydrophobic carbon-based film is affected by many factors, mainly related to the chemical structure of the film surface, and also to sp3. The ratio of /sp2 is also related to the surface roughness. 26. When the surface of the film contains more hydrophobic groups, the hydrophobicity of the film will be significantly enhanced. The monomer of polytetrafluoroethylene is -CF2, so it The hydrophobicity is the strongest, and the nano-scratching loading of the contact film with water is related to the scratch displacement. Fig.8 Normalloadand frictionction angle is 110*. Simultaneously printing the increase of the 3 bond content, the polarization of the 7T electron will cause the surface tension polar component Decrease, the hydrophobicity of the film is enhanced 281; the smooth film surface will repel the adsorption of water on the surface * Experiments show that the hydrophobic property of fluorinated amorphous carbon film (aC:F) The most influential is that the surface structure of the film increases gradually with the degree of fluorination, and excessive hydrophobic C-F2 and C-F3 bonds are formed on the surface of the film, resulting in an increase in the hydrophobicity of the film. In order to use the pulsed magnetic filtration cathode vacuum arc source deposition process to synthesize the change pattern of the contact angle of the film, the contact angle between the film and the double-distilled water gradually increases with the increase of the CF4 flow rate. When the fluorination degree of the film is the largest, it is close to Polytetrafluoroethylene (PTFE).
4 Conclusions With the gradual increase of the CF4 flow, the degree of fluorination of the film gradually increased, the film showed a typical diamond-like structure, and the disorder of the film increased.
Due to the etching effect of -CF, the surface of the film is more densified and the roughness is gradually reduced. The mechanical properties of the film are good, and the hardness is all above 12 GPa.
As the degree of fluorination of the film increases, hydrophobic -CF*;c=l,2,3) groups are formed on the surface of the film, so that the hydrophobic property of the film is enhanced and the maximum contact angle with the double distilled water is reached. 106*, close to polytetrafluoroethylene (PTFE), comprehensive research shows that the use of novel pulsed magnetic filter cathode vacuum arc source deposition technology to synthesize fluorinated diamond-like carbon film effectively lifts the degree of fluorination of the film and synthesizes hydrophobic The performance is close to that of PTFE and the mechanical properties are much better than that of PTFE. The film is expected to find application in the surface modification of medical devices.
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