Improvement in the hydrophilic property of inner surface of polyvinyl chloride tube by DC glow discharge plasma
Introduction
Polymer tubes have been widely used in the medical and biological field, for applications such as catheters, conduits, heart valves, vascular graft, or, dialysis systems. However, when the internal diameter of the polymer tube is very small (e.g., <5 mm), the hydrophobic inner surface of the polymer tubes leads to unwanted protein adsorption and cell adhesion [1], [2], [3]. It is of increasing interest to modify the inner surface of the polymer tubes to transform them into products with high bio-compatibility.
A wide range of surface treatment techniques have been developed to modify the properties of polymer surfaces without changing polymer bulk properties, such as low temperature plasmas, UV-light, electron beams, ion beams, X-rays and lasers [4], [5], [6]. Among these techniques, the low temperature plasma treatment is probably the most versatile one. The active species generated in the plasma interact with polymeric chains on the polymer surface, inducing etching, grafting, polymerization, cross-linking on the surface [7], [8], [9], [10]. Thus the treatment can modify the surface properties of polymer to satisfy various applications. Most studies of plasma-modified polymer material usually employed a plasma reactor to modify the plane surface of a small disk or film substrate [11], [12]. Such reactors are not suitable for inner surface modification of narrow polymer tubes, because the plasma itself cannot penetrate into the tube to achieve a homogeneous modification of the inner surface [13], [14].
Techniques capable of creating plasma inside the polymer tubes are desired for homogeneous modification of the inner surface. In the recent decade, a variety of techniques generating atmospheric [15], [16], [17] or low pressure [18], [19], [20], [21], [22], [23], [24] discharge plasma inside the polymer tube have been proposed. For example, Prat [18] and his coworkers developed a special electrode comprising two copper plates helically wound around a cylindrical glass, to produce an atmospheric glow discharge inside a PVC tube with 6.5 mm inner diameter by applying a high voltage alternating current with a frequency of 20 kHz across the electrode. Kitazaki and Hayashi [16] suggested an approach to produce low pressure discharge plasma inside a silicon rubber tube by ac high voltage.
We have developed an approach to generate a DC glow discharge plasma inside the polymer tubes. In the present work, the inner surface of polyvinyl chloride (PVC) tube with 4 mm inner diameter and 50 mm length were treated by Ar plasma generated inside the tube. Improvement in the hydrophilic property of inner surface of PVC tubes was studied by measuring the water contact-angle. The effect of treatment time, applied voltage and working pressure on hydrophilic property of inner surface of the PVC tube was investigated.
Section snippets
Apparatus
The scheme of experimental setup is shown in Fig. 1. A copper rod anode of 5 mm in diameter was placed in a stainless steel vacuum chamber of length 340 mm and 280 mm diameter and acts as a cathode. The vacuum chamber was evacuated to 10−1 Pa by a rotary pump and then pure argon (99.99%) was introduced into the chamber through a mass flow controller to sustain the working pressure. PVC tubes of 4 mm in inner diameter and 50 mm in length were treated. One end of the PVC tube was directly
Result and discussion
The effect of treatment time, applied voltage and working pressure on hydrophilic property of inner surface of the PVC tube was investigated.
Fig. 4a shows the evolution of the water contact-angle of the inner surface of the plasma-treated PVC tubes measured 20 mm away from the anode as a function of treatment time. The applied voltage and the working pressure were fixed at 700 V and 40 Pa, respectively. The water contact-angle of the untreated inner surface of the tube is 75° and rapidly
Conclusion
A method to generate DC glow discharge plasma inside the polymer tubes has been developed. The inner surface of PVC tubes with 4 mm inner diameter and 50 mm length were treated by Ar plasma generated inside the tube. Significant and homogeneous improvement on the hydrophilic property of the inner surface of the PVC tube was achieved by the Ar plasma treatment. The water contact-angle of the inner surface decreased to 37° from 75° for the untreated sample as the treatment time increased to
Acknowledgement
This work was supported by the Natural Science Foundation of China under Grant No. 50307002. The authors would like to thank Professor Ren Chunsheng for his technical support in contact-angle measurement.
References (28)
- et al.
Thromb Res
(1986) - et al.
Appl Surf Sci
(2003) - et al.
Surf Sci Rep
(1996) - et al.
Biomol Eng
(2002) - et al.
Thin Solid Films
(1998) - et al.
Polymer
(2000) - et al.
Thin Solid Films
(2001) - et al.
Thin Solid Films
(2006) - et al.
Thin Solid Films
(2006) - et al.
Surf Coatings Technol
(2003)
Surf Coat Technol
J Biomed Mater Res
J Biomater Sci Polym Ed
Thin Solid Films
Cited by (11)
Deposition of diamond-like carbon films on interior surface of long and slender quartz glass tube by enhanced glow discharge plasma immersion ion implantation
2015, Surface and Coatings TechnologyCitation Excerpt :Owing to the excellent properties of DLC films, deposition on inner areas has aroused interest for applications to pipes [8], large aspect ratio dies [9], vascular grafts [10,11], and so on. For instance, Baba et al. [12,13] have developed a plasma-based ion implantation (PSII) method to deposit on the interior surface of steel tubes 200 mm long and 20 mm in inner diameter and Wen et al. [14] have treated the inner surface of 50 mm long and 4 mm diameter PVC tubes using a direct current glow discharge plasma source. Ohgoe et al. [15] have proposed a method to deposit DLC on the inside surface of 100 mm long polycarbonate tubes with an inner diameter of 10 mm using a cylindrical electrode producing a radio frequency glow discharge plasma.
Structural and optical properties of chlorinated plasma polymers
2011, Thin Solid FilmsCitation Excerpt :The graph is characterized by the increase in θ from ~ 40° to ~ 77° for the chlorinated material. The contact angles of ~ 77° are very close to that reported recently for PVC, namely 75° [21]. Chlorine is electronegative such that chlorinated polymers may be expected to be more hydrophobic and therefore exhibit greater contact angles than the unchlorinated material.
An atmospheric pressure plasma device with multiple ring electrodes for decontamination of flexible tubing with variable scales
2023, Plasma Processes and PolymersHomogeneous surface hydrophilization on the inner walls of polymer tubes using a flexible atmospheric cold microplasma jet
2020, Plasma Processes and PolymersSurface modification of poly(Vinylchloride) for manufacturing advanced catheters
2020, Current Medicinal Chemistry