Dielectric properties and in vitro hemocompatibility of Nd:YAG laser-irradiated polyethylene terephthalate.

Abstract

Surface properties and morphology of the biomaterial play an essential role in the polymer-material interaction. In this work, laser surface modification of polyethylene terephthalate as a polymer with distinguished mechanical properties was carried out using (neodymium-doped yttrium aluminum garnet) Nd:YAG laser (1.064 µm) with different output power (0.3, 3, and 6 W). The structural, surface, and dielectric properties of PET before and after laser irradiation have been studied using attenuation total reflection-Fourier transform infrared (ATR-FTIR), dielectric spectroscopy (DS), scanning electron microscope (SEM), and contact angle measurements. Moreover, the anticoagulant properties of the laser-irradiated PET was determined through measuring the prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR). In vitro platelet adhesion test was used to assess the platelets adhered to the surface of the samples; in addition to hematological study. It was found that contact angle (θ) measurements of laser-irradiated PET samples decreased compared to the unirradiated PET. The irradiated samples at 0.3 W have the lowest contact angle which is a clear indication that surface treatment with Nd:YAG laser brought about improving the wettability of the polymer. From the dielectric measurements, both values of permittivity and dielectric loss decrease by increasing the laser power. The electrical conductivity decreases with increasing laser power, but still in the same order 10^-14 S/cm. The decrease in electrical conductivity σ may be due to the cross-linking of the polymeric matrix which led to a decrease in the total polarity and consequently decrease in electrical conductivity. The magnitude of σ obtained is highly recommended to be used for insulator purposes in addition to the main purpose that is blood contact.