Plasma Immersion Ion Implantation-deposition Research Articles

Cell-selective titanium oxide coatings mediated by coupling hafnium-doping and UV pre-illumination

Cell-selective biomaterials, i.e. favoring the functions of gingival cells and simultaneously reducing the adhesion of pathogenic bacteria, is highly desired in dental implants. However, due to the same mechanisms shared in attachment by mammalian and microbial cells, it is hard to increase the functions of the former while acting against the latter. Herein, a cell-selectivity was established on titanium oxide coatings by combining a plasma immersion ion implantation & deposition (PIII) and a UV pre-illumination. The titanium oxide coatings were produced on pure titanium substrates by using a plasma electrolytic oxidation technique and then doped of hafnium (Hf) by using a cathodic arc sourced PIII. The Hf-doped titanium oxide coatings (Hf-PIII groups) were capable of delaying the recombination of UV-illumination generated electron-hole pairs, which decreased the adhesion of bacterial cells at the later period (cultured for 24 h). Titanium oxide coating doped of 4.87 at.% hafnium (Hf) gained the biggest decrease (decreased 52.9% compared to its UV negative counterparts) in bacterial adhesion among the UV positive (UV+) groups. This study demonstrates that coupling Hf-doping and UV pre-illumination is promising for improving the cell-selective performance of titanium-based dental implants.

Characterization of amorphous carbon films by PECVD and plasma ion implantation: The role of fluorine and sulfur doping

We carry an investigation on the structural and optical properties of amorphous carbon films, containing fluorine and sulfur in their composition, grown by plasma enhanced chemical vapor (PECVD) and plasma immersion ion implantation deposition (PIIID) techniques. The films were grown by a combination of acetylene, sulfur hexafluoride, and argon gases. The chemical and optical properties of the films, prepared with different gas concentrations and voltages on the substrate, are analyzed by X-ray photoelectron spectroscopy and Fourier-transform infrared absorption spectroscopy. The results indicate that the application of negative pulses in the lower electrode allows greater incorporation of fluorine atoms with a smaller amount of hexafluoride gas at the reactor feed. Additionally, sulfur incorporation has been detected in the films in concentrations up to 18%. The influence of the incorporation of fluorine and sulfur on the optical properties is also explored.

The investigation of the structures and tribological properties of F-DLC coatings deposited on Ti-6Al-4V alloys

Fluorine doped diamond-like carbon (F-DLC) coatings were deposited on Ti-6Al-4V alloy using a hollow cathode plasma immersion ion implantation deposition system. The aim of this work is to investigate the influence of F content on the surface morphology, structure, mechanical and tribological properties (under air and stroke-physiological saline solution) of the F-DLC coatings. The results reveal that the ratio of H/fE instead of H/E can be well predicting the anti-wear results when the F-DLC coatings have enough adhesion strength, where H is hardness, E is Young's modulus and f is friction coefficient. The F-DLC coatings with high F content exhibit excellent tribological property under air. The low F content F-DLC coatings present super-low friction coefficient and wear rate in stroke-physiological saline solution. Reasons for the tribological property are proposed in combination with the films' morphology and mechanical property.

Plasma-Wall Interaction Facilities in Korea

Although the research of plasma-material interaction (PMI) is rather immature comparing the recent success of Korean fusion program, there are several facilities and programs of PMI research in Korea. DiPS (Divertor Plasma Simulator)-2 is a linear device with a four-inch-LaB6 cathode at the Center for Edge Plasma Science (cEps), concentrating on the development of various diagnostics for divertor and scrape-off plasmas, and for PMI research such as tungsten and graphite related phenomena. This is modified from DiPS-1, which were for the simulations of divertor, space and processing plasmas using LaB6 and helicon plasma sources. MP2 (Multi-Purpose Plasma) is a linear device with an eight-inch-LaB6 cathode for PMI in National Fusion Research Institute (NFRI), and will be merged with molten salt (FLiNaK) experiment by using an Electron Cyclotron Resonance (ECR) plasma source. High power plasma torch facilities have been developed at the High-Enthalpy Plasma Research Center in ChonBuk National University, aiming for the development of new materials of the aerospace-, nano-, and automobile-industries, yet recently they have interest in fusion materials. Plasma Immersion Ion Implantation & Deposition (PIIID) facility has been utilized for the research of processing materials in Korean Institute of Science and Technology (KIST), and is to be used for fusion material researches with high energy ions (~70 keV). Electron beam irradiation has been tried for the research of graphite and tungsten at DanKook university. These facilities are to be utilized for the application to KSTAR, ITER and/or Korean DEMO fusion devices. Dust as the by-product of PMI in fusion device is to be characterized and removed in TReD (Transport & Removal experiment of Dust) device in Hanyang University. Plasma sources, diagnostics, and surface analyses of these programs will be explained with design philosophies and basic parameters of plasmas.

Tantalum coated NiTi alloy by PIIID for biomedical application

Plasma immersion ion implantation deposition (PIIID) technique was employed to fabricate tantalum coatings on NiTi alloys with the aim to obtain a more adherent, corrosion resistant and radiopaque coatings in our present study. The surface characteristics and corrosion behavior were investigated by SEM, AFM, XRD, AES, XPS and electrochemical measurement. The results show that a relatively rough, dense and adhesive tantalum coating has been successfully fabricated on NiTi alloy by the PIIID method with the thickness of about 3.3μm. The surface topography of the tantalum coatings is characterized by regularly spaced grain facets. The coating is combined with a mixture of predominantly α-phase tantalum with a small concentration of β-phase tantalum. The outmost surface of the coating is oxidized, consisting of majority of stoichiometric Ta2O5 and a small quantity of Ta2O5−X. It can be concluded that the dense and adhesive tantalum coatings on NiTi alloy improve its corrosion resistance, implying the decrease of Ni ions released into human body fluids.

Torsional fretting wear of a biomedical Ti6Al7Nb alloy for nitrogen ion implantation in bovine serum

Ti6Al7Nb is a high-strength titanium alloy used in replacement hip joints that possesses the excellent biocompatibility necessary for surgical implants. Ti6Al7Nb treated with nitrogen gas (N2) plasma immersion ion implantation–deposition (PIII–D) was investigated. Torsional fretting wear tests of untreated and nitrogen-ion-implanted Ti6Al7Nb alloys against a Zr2O ball (diameter 25.2mm) were carried out under simulated physiological conditions (serum solution) in a torsional fretting wear test rig. Based on the analyses of the frictional kinetics behavior, the observation of 3D profiles, SEM morphologies and surface composition analyses, the damage characteristics of the surface modification layer and its substrate are discussed in detail. The influence of nitrogen ion density on the implantation and torsional angular displacement amplitudes were investigated. The results indicated that ion implantation layering can improve resistance to torsional fretting wear and thus has wide potential application for the prevention of torsional fretting damage in artificial implants. The damage mechanism prevented by the ion implantation layer on the Ti6Al7Nb alloy is a combination of oxidative wear, delamination and abrasive wear. An increase in ion implantation concentration inhibited detachment by delamination.

Wettability and bloodcompatibility of a-C:N:H films deposited by PIII-D

Abstract Wettability of amorphous carbon films can be adjusted by doping with other elements, including F, Si, Ti, O and N. In this study, nitrogen-doped hydrogenated amorphous carbon (a-C:H:N) films were deposited on silicon wafers (100) by plasma immersion ion implantation–deposition (PIII-D) using C2H2 + N2 gas mixtures. Film composition and bonding structure were analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Surface morphology of the films was characterized using an extended multimode nanoscope atomic force microscope (AFM). Wettability examination was performed using the sessile drop method. Bloodcompatibility of the films was assessed by in vitro platelet adhesion test. The results suggest that a-C:N:H film synthesized at the highest N2/C2H2 flux ratio of 2/1 presents better anti-thrombotic property than the low temperature isotropic pyrolytic carbon (LTIC) and this improvement of bloodcompatibility can owe to the increase of hydrophilicity of the film caused by N incorporation in the carbon network and additional increase of surface roughness.

Investigation of cytocompatibility of surface-treated cellulose nitrate films by using plasma immersion ion implantation

The alpha-particle sensitive colorless cellulose nitrate films (commercially available as LR 115 films from DOSIRAD, France) have been proposed as cell-culture substrates for alpha-particle radiobiological experiments. Cytocompatibility of the substrate is a key factor to the success of such experiments. The present work aims to investigate the cytocompatibility of surface-treated cellulose nitrate films by using plasma immersion ion implantation–deposition. The films were placed in a vacuum chamber, into which nitrogen gas was continuously bled and where the pressure was kept at 2 × 10 − 3 Torr. Implantation was carried out by igniting the nitrogen plasma at 100 W radio-frequency and applying high bias voltage in pulse with 20 μs pulse width and 50 Hz (with 20 kV or no voltage). HeLa cervix cancer cells were then cultured on both the plasma-treated and untreated cellulose nitrate films. Our tests showed that the plasma-treated films are in general more cytologically compatible.

In vitro platelet adhesion and activation of polyethylene terephthalate modified by acetylene plasma immersion ion implantation and deposition

Acetylene (C2H2) plasma immersion ion implantation–deposition (PIII–D) was conducted on polyethylene terephthalate (PET) to improve its blood compatibility. The platelet adhesion and activation behavior of PET treated by C2H2 PIII–D at different working pressures was investigated. Raman spectroscopy results show that amorphous carbon films were successfully deposited on the PET surfaces. X-ray photoelectron spectroscopy (XPS) analysis indicates that carbon films of various sp2/sp3 composition are formed at different working pressures and the sp3 hybridized C content in the films increases as a function of pressure. Platelet adhesion experiments were conducted to examine the blood compatibility in vitro. Optical microscopy reveals that the amounts of adherent platelets on all modified PET films are less than that on the untreated surface. The adhered platelets on carbon films deposited at 0.5Pa and 1.0Pa working pressure are about 32% and 55%, respectively, of that for the untreated PET surface. The platelets are observed to be isolated and round on carbon films deposited at 0.5Pa, indicating that fewer platelets are activated on the amorphous carbon films. These results thus shows that amorphous carbon films deposited on PET by C2H2 PIII–D suppress platelet adhesion and activation, and the extent of the improvement is related to the structure of the carbon films.

Formation of silicon-on-aluminum nitride using ion-cut and theoretical investigation of self-heating effects

We propose to replace the buried SiO 2 layer in silicon-on-insulator (SOI) with a plasma-synthesized AlN thin film to mitigate the self-heating penalty. The AlN films synthesized on Si by metal plasma immersion ion implantation–deposition (Me-PIIID) exhibit outstanding surface topography and excellent insulating characteristics. Using direct bonding process and the hydrogen-induced layer transfer method, a silicon-on-AlN (SOAN) structure has been successfully fabricated. Cross-sectional high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) depth profiles and spreading resistance probe (SRP) reveal that a uniform buried AlN layer is under a single crystal Si overlayer. The interfaces between the top Si layer, buried AlN layer, and Si substrate are smooth and sharp. In addition, the new SOAN device has been verified in two-dimensional device simulation and demonstrates that the self-heating penalty of SOI can indeed be reduced using SOAN substrates.

Effect of annealing on structure and biomedical properties of amorphous hydrogenated carbon films

The usual failure of blood-contacting biomedical materials and devices arises from thrombogenesis. When a biomaterial comes in contact with a biological body, interface interaction will be concomitant between the biomaterial surface and biological substance, such as blood protein denaturation resulting from electrical charge transfer of proteins and platelet activation induced by interface thermodynamics. Diamond-like carbon (DLC) has been proposed for use in blood contacting devices. Further understanding of the intrinsic relationship between biomedical properties and structure of amorphous carbon films will promote improvement of their biocompatibility. In this study, hydrogenated amorphous carbon (a-C:H) films were fabricated at room temperature using plasma immersion ion implantation-deposition (PIII-D). A series of a-C:H films with different structures and chemical bonds were obtained by adjusting the DC bias voltage from −75 to −900 V, then their structure and physical properties were further modified by thermal anneal in vacuum at 600 °C. Raman, elastic recoil detection (ERD) and atomic force microscope (AFM) were used to characterize their structures and chemical bonds. The physical properties and surface characteristics of the films were also examined, including the carrier concentration and mobility, resistivity, and surface wettability. The anticoagulation of the films was evaluated employing in vitro platelet adhesion test. The adhesion, activation, and morphology of the platelets were investigated using scanning electron microscopy (SEM). The relationship between their structure and blood compatibility was elucidated.

Bacterial repellence from polyethylene terephthalate surface modified by acetylene plasma immersion ion implantation–deposition

There is an increasing interest in developing new methods to reduce bacterial adhesion onto polymeric materials used in biomedical implants. The antibacterial adsorption behavior on polyethylene terephthalate (PET) treated by plasma immersion ion implantation–deposition (PIII–D) using acetylene (C 2H 2) at different working pressures is investigated . The surface structure of the treated PET is determined by Rutherford backscattering spectrometry (RBS), laser Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results show the formation of thin hydrogenated amorphous carbon (a-C:H) films with different structures and chemical bonds on the PET surface. The ability of Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) to adhere to PET is quantitatively determined by plate counting and Gamma-ray counting of the 125I-labeled bacteria in vitro. The adhesion efficiency of SA on the a-C:H film deposited at 0.5 Pa of working pressure is about 16% of that on the untreated PET surface, and the adhered bacterial concentration of SE on the carbon film deposited at 1.0 Pa is about 1/6 of that of the PET surface. Bacterial adhesion onto a-C:H films is influenced by the structures and chemical bonds of the materials. The reduction in bacterial adhesion can be explained by the free energy of adhesion (Δ F Adh), which predicts whether microbial adhesion is energetically favorable (Δ F Adh<0) or not (Δ F Adh>0). Our results show that bacterial adhesion is energetically unfavorable on the a-C:H films deposited at 0.5 and 1.0 Pa, and this study suggests one possible method to repel bacteria from polymeric surfaces.

Hemocompatibility of nitrogen-doped, hydrogen-free diamond-like carbon prepared by nitrogen plasma immersion ion implantation-deposition.

Amorphous hydrogenated carbon (a-C:H) has been shown to be a potential material in biomedical devices such as artificial heart valves, bone implants, and so on because of its chemical inertness, low coefficient of friction, high wear resistance, and good biocompatibility. However, the biomedical characteristics such as blood compatibility of doped hydrogen-free diamond-like carbon (DLC) have not been investigated in details. We recently began to investigate the potential use of nitrogen-doped, hydrogen-free DLC in artificial heart valves. In our experiments, a series of hydrogen-free DLC films doped with nitrogen were synthesized by plasma immersion ion implantation-deposition (PIII-D) utilizing a pulsed vacuum arc plasma source and different N to Ar (FN/FAr) gas mixtures in the plasma chamber. The structures and properties of the film were evaluated by Raman spectroscopy, Rutherford backscattering spectrometry (RBS), and X-ray photoelectron spectroscopy (XPS). To assess the blood compatibility of the films and the impact on the blood compatibility by the presence of nitrogen, platelet adhesion tests were conducted. Our results indicate that the blood compatibility of both hydrogen-free carbon films (a-C) and amorphous carbon nitride films are better than that of low-temperature isotropic pyrolytic carbon (LTIC). The experimental results are consistent with the relative theory of interfacial energy and surface tension including both dispersion and polar components. Our results also indicate that an optimal fraction of sp2 bonding is desirable, but an excessively high nitrogen concentration degrades the properties to an extent that the biocompatibility can be worse than that of LTIC.

Bacterial repellence from polyethylene terephthalate surface modified by acetylene plasma immersion ion implantation?deposition

There is an increasing interest in developing new methods to reduce bacterial adhesion onto polymeric materials used in biomedical implants. The antibacterial adsorption behavior on polyethylene terephthalate (PET) treated by plasma immersion ion implantation–deposition (PIII–D) using acetylene (C 2 H 2 ) at different working pressures is investigated . The surface structure of the treated PET is determined by Rutherford backscattering spectrometry (RBS), laser Raman spectroscopy , and X-ray photoelectron spectroscopy (XPS). The results show the formation of thin hydrogenated amorphous carbon (a-C:H) films with different structures and chemical bonds on the PET surface. The ability of Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) to adhere to PET is quantitatively determined by plate counting and Gamma-ray counting of the 125 I-labeled bacteria in vitro. The adhesion efficiency of SA on the a-C:H film deposited at 0.5 Pa of working pressure is about 16% of that on the untreated PET surface, and the adhered bacterial concentration of SE on the carbon film deposited at 1.0 Pa is about 1/6 of that of the PET surface. Bacterial adhesion onto a-C:H films is influenced by the structures and chemical bonds of the materials. The reduction in bacterial adhesion can be explained by the free energy of adhesion (Δ F Adh ), which predicts whether microbial adhesion is energetically favorable (Δ F Adh <0) or not (Δ F Adh >0). Our results show that bacterial adhesion is energetically unfavorable on the a-C:H films deposited at 0.5 and 1.0 Pa, and this study suggests one possible method to repel bacteria from polymeric surfaces.

Synthesis of aluminum nitride films by plasma immersion ion implantation–deposition using hybrid gas–metal cathodic arc gun

Aluminum nitride (AlN) is of interest in the industry because of its excellent electronic, optical, acoustic, thermal, and mechanical properties. In this work, aluminum nitride films are deposited on silicon wafers (100) by metal plasma immersion ion implantation and deposition (PIIID) using a modified hybrid gas–metal cathodic arc plasma source and with no intentional heating to the substrate. The mixed metal and gaseous plasma is generated by feeding the gas into the arc discharge region. The deposition rate is found to mainly depend on the Al ion flux from the cathodic arc source and is only slightly affected by the N2 flow rate. The AlN films fabricated by this method exhibit a cubic crystalline microstructure with stable and low internal stress. The surface of the AlN films is quite smooth with the surface roughness on the order of 1/2 nm as determined by atomic force microscopy, homogeneous, and continuous, and the dense granular microstructures give rise to good adhesion with the substrate. The N to Al ratio increases with the bias voltage applied to the substrates. A fairly large amount of O originating from the residual vacuum is found in the samples with low N:Al ratios, but a high bias reduces the oxygen concentration. The compositions, microstructures and crystal states of the deposited films are quite stable and remain unchanged after annealing at 800 °C for 1 h. Our hybrid gas–metal source cathodic arc source delivers better AlN thin films than conventional PIIID employing dual plasmas.

Characteristics and anticoagulation behavior of polyethylene terephthalate modified by C2H2 plasma immersion ion implantation-deposition

Acetylene (C2H2) plasma immersion ion implantation-deposition (PIII-D) is conducted on polyethylene terephthalate (PET) to improve its blood compatibility. The structural and physicochemical properties of the modified surface are characterized by, Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), and static contact angle measurement. Atomic force microscopy discloses that the average roughness (Ra) of film surface decreases from 58.9 nm to 11.4 nm after C2H2 PIII-D treats PET. Attenuated total reflection Fourier transform infrared spectroscopy shows that the specfic adsorption peaks for PET decrease after ion implantation and deposition. Raman spectroscopy indicates that a thin amorphous polymerlike carbon (PLC) film is formed in the PET. The effects of the surface modification on the chemical bonding of C, H, and O are examined by XPS and the results show that the ratio of sp3 C–C to sp2 C=C is 0.25. After C2H2 PIII-D, the polar component γp of surface energy increases from 2.4 mN/m to 12.3 mN/m and γp/γd increases from 0.06 to 0.35. The wettability of the modified surfaces is improved. Scanning electron microscopy and optical microscopy reveal that the amounts of adhered, aggregated and morphologically changed platelets are reduced by the deposition of an amorphous polymer-like carbon film. The thrombin time, prothrombin time, and activated partial thromboplastin time of the modified PET are longer than those of the untreated PET. Our result thus shows that the amorphous PLC film deposited on the PET surface by C2H2 PIII-D improves platelet adhesion and activation.

Structure and properties of annealed amorphous hydrogenated carbon (a-C:H) films for biomedical applications

When a biomaterial comes in contact with a biological body, biological substance denaturation will be concomitant with the physical interaction between the biomaterial surface and biological substance, such as blood protein denaturation resulting from electrical charge transfer. In this study, we investigated the relationship between the physical properties of amorphous hydrogenated carbon (a-C:H) and its blood compatibility. The films were fabricated using plasma immersion ion implantation-deposition (PIII-D), followed by annealing in vacuum between 200 and 600 °C. A series of a-C:H films with different structures and chemical bonds were characterized by Raman, elastic recoil detection (ERD) and atomic force microscopy (AFM). The results indicate that hydrogen effusion and film graphitization are promoted at high annealing temperature. The physical properties and surface characteristics of the films including the carrier concentration and mobility, resistivity, band gap and surface wettability were also examined. Their changes with anneal temperature are due to the increase of sp2 bonding cluster caused by graphitization. The thrombogenesis of the films was evaluated employing in vitro platelet adhesion tests. The adhesion, activation, and morphology of the platelets were investigated using scanning electron microscopy (SEM). The results were correlated with the biological data to elucidate the blood compatibility mechanism of a-C:H films. The platelet adhesion and activation of a-C:H is affected by annealing. It is believed that the possible factors affecting blood compatibility are the adhesion energy of blood plasma, band gap, carrier type and concentration. Improving the electronic structure of a-C:H films is critical to the abatement of platelet activation.

Structure and properties of annealed amorphous hydrogenated carbon (a-C:H) films for biomedical applications

When a biomaterial comes in contact with a biological body, biological substance denaturation will be concomitant with the physical interaction between the biomaterial surface and biological substance, such as blood protein denaturation resulting from electrical charge transfer. In this study, we investigated the relationship between the physical properties of amorphous hydrogenated carbon (a-C:H) and its blood compatibility. The films were fabricated using plasma immersion ion implantation-deposition (PIII-D), followed by annealing in vacuum between 200 and 600 °C. A series of a-C:H films with different structures and chemical bonds were characterized by Raman, elastic recoil detection (ERD) and atomic force microscopy (AFM). The results indicate that hydrogen effusion and film graphitization are promoted at high annealing temperature. The physical properties and surface characteristics of the films including the carrier concentration and mobility, resistivity, band gap and surface wettability were also examined. Their changes with anneal temperature are due to the increase of sp 2 bonding cluster caused by graphitization. The thrombogenesis of the films was evaluated employing in vitro platelet adhesion tests. The adhesion, activation, and morphology of the platelets were investigated using scanning electron microscopy (SEM). The results were correlated with the biological data to elucidate the blood compatibility mechanism of a-C:H films. The platelet adhesion and activation of a-C:H is affected by annealing. It is believed that the possible factors affecting blood compatibility are the adhesion energy of blood plasma, band gap, carrier type and concentration. Improving the electronic structure of a-C:H films is critical to the abatement of platelet activation.

Flexible system for multiple plasma immersion ion implantation-deposition processes

Multiple plasma immersion ion implantation-deposition offers better flexibility compared to other thin film deposition techniques with regard to process optimization. The plasmas may be based on either cathodic arc plasmas (metal ions) or gas plasmas (gas ions) or both of them. Processing parameters such as pulsing frequency, pulse duration, bias voltage amplitude, and so on, that critically affect the film structure, internal stress, surface morphology, and other surface properties can be adjusted relatively easily to optimize the process. The plasma density can be readily controlled via the input power to obtain the desirable gas-to-metal ion ratios in the films. The high-voltage pulses can be applied to the samples within (in-duration mode), before (before-duration mode), or after (after-duration mode) the firing of the cathodic arcs. Consequently, dynamic ion beam assisted deposition processes incorporating various mixes of gas and metal ions can be achieved to yield thin films with the desirable properties. The immersion configuration provides to a certain degree the ability to treat components that are large and possess irregular geometries without resorting to complex sample manipulation or beam scanning. In this article we describe the hardware functions of such a system, voltage–current behavior to satisfy the needs of different processes, as well as typical experimental results.

The effects of amorphous carbon films deposited on polyethylene terephthalate on bacterial adhesion

There is an increasing interest in developing new methods to reduce bacteria adhesion onto polymeric materials that are used in biomedical implants. The antibacterial behavior on polyethylene terephthalate (PET) treated by acetylene (C 2H 2) plasma immersion ion implantation-deposition (PIII-D) is investigated. The surface structure of the treated PET is determined by laser Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The results show that a thin amorphous polymer-like carbon (PLC) layer is formed on the PET surface. Atomic force micrographs (AFM) show that C 2H 2 PIII-D significantly changes the surface morphology of PET. The capacities of Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) to adhere onto PET are quantitatively determined by plate counting and Gamma-ray counting of 125I radio labeled bacteria in vitro. The results indicate that the adhesion of the two kinds of bacteria to PET is suppressed by PLC. The adhesion efficiency of SE on the coated surface is only about 14% of that of the untreated PET surface, and that of SA is about 35% of that of the virgin surface. The electrokinetic potentials of the bacterial cells and substrates are determined by zeta potential measurement. All the substrates as well as the bacterial strain have negative zeta potentials, and it means that bacterial adhesion is not mediated by electrostatic interactions. The surface energy components of the various substrates and bacteria are calculated based on measurements in water, formamide and diiodomethane. The surface free energies obtained are used to calculate the interfacial free energies of adhesion (Δ F Adh) of SA and SE onto various substrates, and it is found that bacterial adhesion is energetically unfavorable on the PLC deposited on PET by C 2H 2 PIII-D.