Influence of bias voltage on diamond like carbon (DLC) film deposited on polyethylene terephthalate (PET) film surfaces using PECVD and its blood compatibility

Pandiyaraj, K.N.,V. Selvarajan,Heeg, J.,Junge, F.,Lampka, A.,Barfels, T.,Wienecke, M.,Rhee, Y.H.,Kim, H.W. Elsevier 2010 Diamond and related materials Vol.19 No.7

In this paper, diamond like carbon (DLC) films were coated on polyethylene terephthalate (PET) film substrate as a function of biasing voltage using plasma enhanced chemical vapour deposition. The surface morphology of the DLC films was analyzed by scanning electron microscopy and atomic force microscopy. The chemical state and structure of the films were analyzed by X-ray photoelectrons spectroscopy and Raman spectroscopy. The micro hardness of the DLC films was also studied. The surface energy of interfacial tension between the DLC and blood protein was investigated using contact angle measurements. In addition, the blood compatibility of the films was examined by in vitro tests. For a higher fraction of sp<SUP>3</SUP> content, maximum hardness and surface smoothness of the DLC films were obtained at an optimized biasing potential of -300V. The in vitro results showed that the blood compatibility of the DLC coated PET film surfaces got enhanced significantly.

Glow discharge plasma-induced immobilization of heparin and insulin on polyethylene terephthalate film surfaces enhances anti-thrombogenic properties

Pandiyaraj, K.N.,Selvarajan, V.,Rhee, Y.H.,Kim, H.W.,Shah, S.I. Elsevier 2009 Materials science & engineering. C, Materials for Vol.29 No.3

Polyethylene terephthalate (PET) films were treated with DC glow discharge plasma followed by graft copolymerization with acrylic acid (AA) and polyethylene glycol (PEG). The obtained PET-PEG was coupled to heparin or insulin molecules. The surfaces were then characterized by contact angle measurements, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The surface energies of the modified PET films were estimated using contact angle measurements, and the changes in crystallinity of the plasma-modified PET film surfaces were investigated by X-ray diffraction (XRD) analysis. The blood compatibilities of the surface-modified PETs were examined by in vitro thrombus formation, whole blood clotting time, platelet contact and protein adsorption experiments. The results revealed that the contact angle value decreased and that the interfacial tension between the modified PET films and blood protein was drastically diminished compared to unmodified PET film. The XPS results showed that the PET-AA surface containing carboxylic acid and the immobilized PET surface containing both carboxylic acid and amino groups exhibited a hydrophilic character, and AFM results showed marked morphological changes after grafting of AA, PEG and biomolecule immobilization. Heparin and insulin-coupled PET surfaces exhibited much less platelet adhesion and protein adsorption than the other surface-modified PET film surfaces.

Effect of cold atmospheric pressure plasma gas composition on the surface and cyto-compatible properties of low density polyethylene (LDPE) films

K. Navaneetha Pandiyaraj,A. Arun Kumar,M.C. RamKumar,K. Thirupugalmani,Avi Bendavid,Pi-Guey Su,S. Uday Kumar,P. Gopinath 한국물리학회 2016 Current Applied Physics Vol.16 No.7

In the present investigation, we have studied the influence of oxygen (O2) flow rate in the atmospheric pressure argon (Ar) plasma zone for improvement of the surface and cell compatible properties of LDPE film. Various characterization techniques such as contact angle (CA), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), etc were used to investigate the hydrophilicity, surface chemistry and morphology of LDPE films respectively. Fowke's approximation method was used to evaluate the polar and dispersion components of the total surface energy of LDPE films using contact angle values of three testing liquids. Moreover T-peel and lap shear tests were used to analyze the adhesive strength of the surface modified LDPE films. Finally cyto-compatibility of the surface modified LDPE film was analyzed by in vitro cell compatibility analysis which includes the cell viability and adhesion using NIH-3T3 fibroblast cells. The results obtained from various characterization techniques evidently revealed that cold atmospheric pressure (CAP) plasma treatment enhanced the surface properties (hydrophilicity, surface morphology and surface chemistry) of LDPE film. Owing to tailored physico-chemical changes induced by the CAP plasma treatment facilitates improvement in adhesive strength as well as adhesion and proliferation of cells on the surface of LDPE films.

Investigation on surface properties of TiO2 films modified by DC glow discharge plasma

K. Navaneetha Pandiyaraj,V. Selvarajan,Matteo Pavese,Polycarpos Falaras,Dimitrios Tsoukleris 한국물리학회 2009 Current Applied Physics Vol.9 No.5

In the present work, TiO2 films deposited on polyethylene terephthalate substrates by dip coating technique were subsequently treated by DC glow discharge plasma as a function of discharge potential. Hydrophilicity of these TiO2 film surfaces was analyzed by contact angle measurements. Atomic force microscopy (AFM) revealed changes in surface morphology of the plasma treated TiO2 films. Modifications in structural and chemical composition of the TiO2 films were detected by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The blood compatibility of TiO2 films was studied by in vitro investigation which includes thrombus formation and whole blood clotting time analysis (WBCT). It was found that the plasma treatment results in blood compatibility enhancement attributed to the structural, chemical and morphological properties of the modified film surfaces.

Combined effects of direct plasma exposure and pre-plasma functionalized metal-doped graphene oxide nanoparticles on wastewater dye degradation

K. Navaneetha Pandiyaraj,D. Vasu,A. Raji,Rouba Ghobeira,Parinaz Saadat Esbah Tabaei,Nathalie De Geyter,Rino Morent,M.C. Ramkumar,M. Pichumani,R.R. Deshmukh 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

The current study investigates the combinatorial effect of the photocatalytic performance of plasma pretreatedTi-Cu-Zn doped graphene oxide (TCZ-GO) nanoparticles (NPs) and advanced oxidation processesof a non-thermal atmospheric pressure plasma on the degradation of reactive orange-122 (RO-122) dyecompounds. Firstly, in order to enhance the photocatalytic performance of the synthesized compositeNPs, they were subjected to glow discharge plasma treatments operating in different gases (Ar, air, O2and N2). Their surface morphology, chemical composition and band gap were examined by means ofscanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–Vis spectrophotometryrespectively. XPS results revealed that plasma-treated NPs exhibited a higher content of oxygenvacancies and a variation in their oxidation states (Ti4+?Ti3+, Cu+?Cu2+). These plasma-induced surfacechemical changes hindered the recombination of photo-generated electron-hole pairs which led to a dropin the bandgap of the NPs with N2 plasma-treated NPs acquiring the lowest bandgap. Lastly, the articleexamined the actual decomposition of RO-122 dye in wastewater by an Ar plasma treatment alone orcombined with the plasma-treated TCZ-GO NPs via spectrophotometric analyses, electrical conductivity,pH and total organic carbon (TOC) removal measurements. Moreover, the reactive species produced duringthe combined plasma/photocatalysis induced degradation were detected in situ by optical emissionspectroscopy. Results revealed that the processes carried out by combining N2 plasma-treated TCZ-GONPs and Ar plasma exhibited the highest degradation efficiency (85 %) due to the generation of moreOH and H2O2. Overall, it can be concluded that plasma-aided treatment processes used synergisticallyas indirect surface functionalization of TCZ-GO NPs and direct plasma treatment of wastewater are extremelyefficient in the degradation of toxic compounds and can be extrapolated to various environmentalapplications.

Au Nanoparticle-decorated Nanoporous PEDOT Modified Glassy Carbon Electrode: A New Electrochemical Sensing Platform for the Detection of Glutathione

Rajendran Rajaram,Pandiyaraj Kanagavalli,Shanmugam Senthilkumar,Jayaraman Mathiyarasu 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.5

Glutathione (GSH) is an important bio-thiol which is playing vital role in the human system, such as treating glaucoma, preventing asthma, cancer, etc. Therefore, electrochemical sensing of GSH is becoming very vital to know the level of the biomolecule in living systems. Hence, the present work aims to develop a sensor matrix for electrochemical biosensing of GSH at Au nanoparticle decorated Nanoporous poly(3,4)ethylene dioxythiophene (PEDOT) modified glassy carbon electrode (AuNPPEDOT/ GCE). The electrode is modified with a nanoporous fibrillar network of PEDOT containing Au nanoparticles and characterized using UV-Visible spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The platform is capable of producing enhanced signal against the bio-analyte at the applied overpotential of 0.6 V. Whereas bare glassy carbon electrode is unable to produce the signal. Conversely, Nanoporous PEDOT modified glassy carbon electrode can sense GSH of very low sensitivity at an applied overpotential of 0.7 V. From single step chronoamperometric measurements, kinetic parameters such as diffusion coefficient and apparent rate constant of the reaction were found as 5.01 × 10-5 cm2·s-1 and 1.106 × 103 M-1·s-1 respectively. From the amperometric response, the sensitivity and limit of detection (LOD) of the electrode were to be 10.7 μA cm-2/μM and 0.173 μM respectively with the linear range of 0.5 to 10 μM. The matrix can detect GSH in the presence of other possible interfering molecules present in blood samples.