Browsing by Author "Yilmaz, Kurtulus"

Now showing 1 - 6 of 6

Citation - WoS: 2
Citation - Scopus: 2
Highly Conductive and Uniform Pedot on Poly(acrylic Acid-Vinylbenzyl Chloride) Functionalized Surfaces
(Elsevier, 2024) Yilmaz, Kurtulus; Karaman, Mustafa
This study demonstrates increasing the uniformity and conductivity of poly(3,4-ethylene dioxythiophene) (PEDOT) thin films synthesized by vapor phase polymerization (VPP) through the utilization of a thin interfacial prime layer on the substrate surface. The prime layer, which is a copolymer of acrylic acid (AA) and vinylbenzyl chloride (VBC), was coated on the substrate surface using initiated chemical vapor deposition (iCVD) method. FTIR and XPS were used to analyze the structure of as-deposited films. The use of P(AA-VBC) copolymer as a prime layer allowed uniform and complete coverage of the oxidant solution on the substrate surface due to the hydrophilic nature of the AA constituent. During the VPP, the existence of the chlorine ions originating from the VBC constituent allowed in-situ doping of the as-deposited polymer, which contributes to the increased uniformity and the conductivity. The experimental studies were carried out to show the increase in uniformity, conductivity and adherence of the as-deposited PEDOT film in the presence of the prime layer. There was nearly a 4-fold increase in the conductivity of as-deposited PEDOT in the presence of the prime layer, with measured conductivity uniformity as high as 96% over a 5x5 cm2 glass surface.
Large-Area Deposition of Hydrophobic Poly(Hexafluorobutyl Acrylate) Thin Films on Wetting-Sensitive and Flexible Substrates Via Plasma-Enhanced Chemical Vapor Deposition
(Mdpi, 2025) Yilmaz, Kurtulus; Gursoy, Mehmet; Karaman, Mustafa
In this study, hydrophobic poly(hexafluorobutyl acrylate) (PHFBA) thin films were successfully deposited over a large area of 25 x 50 cm using plasma-enhanced chemical vapor deposition (PECVD). Key parameters, including plasma power and the distance between the plasma antenna and the substrate, were optimized to achieve the highest deposition rate while ensuring uniformity and defect-free coatings. The optimal conditions were determined as 5 W plasma power and a 9 cm antenna-substrate distance, yielding a maximum deposition rate of 11.3 nm/min. PHFBA's low fluorine content makes it a more environmentally and biologically friendly alternative compared to heavily fluorinated polymers, addressing concerns about toxicity and environmental impact. The coatings were applied to a flexible and wetting-sensitive paper towel substrate, which was successfully coated without any visible defects. The contact angle measurements confirmed the hydrophobic nature of the films, with a maximum water contact angle of 131.9 degrees after the deposition of PHFBA. This study highlights the potential of PECVD as an efficient and scalable method for producing hydrophobic coatings, combining high-performance properties with improved environmental considerations. The results not only validate PECVD as a scalable and precise method for thin film fabrication but also open new possibilities for its use in applications requiring durable and functional surface modifications.
Citation - WoS: 6
Citation - Scopus: 7
Reel-To Coating of a Conductive Polymer on Synthetic Textile Yarns in a Semi-Closed Batch Oxidative Cvd System
(Korean Fiber Soc, 2024) Karaman, Mustafa; Cam, Serdar Murat; Çelen, Onur; Özbakış, Miray; Yilmaz, Kurtulus
In this manuscript, we demonstrate the ability to use a reel-to-reel processing technology for conductive surface functionalization of textile yarns using oxidative chemical vapor deposition in a continuous manner. We designed and built a vacuum deposition system, which allows the winding of yarns into the oCVD reactor by unreeling from the outside atmosphere, where the yarn is pre-treated with oxidant solution. Iron(III)chloride (FeCl3) and 3,4-ethylenedioxythiophene were used as the oxidant and monomer, respectively, to deposit thin films of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films on the synthetic PET yarn surfaces. FTIR and XPS analyses were carried out to verify the chemical structure of as-deposited PEDOT films. Effects of temperature, oxidant concentration, and winding speed on the electrical conductivities of the yarns after oCVD were studied. All yarns exhibited non-zero conductivity values independent of the deposition conditions studied. Very high conductivity uniformities were observed along the longitudinal direction of the yarns even at the highest studied winding speed of 24 cm/min.
Roll-to Oxidative Chemical Vapor Deposition of Highly Conductive and Uniform Thin Films on Large-Scale Textile Substrates
(Korean Fiber Soc, 2025) Yilmaz, Kurtulus; Karaman, Mustafa
A continuous vapor deposition process is demonstrated for organic conductive surface modification of large-area textile substrates. Transparent and conductive poly(3,4-ethylenedioxythiophene) (PEDOT) films were deposited by oxidative chemical vapor deposition (oCVD) technique on polyethylene terephthalate (PET) fabrics in a roll-to-roll fashion, in which as-deposited PEDOT films had excellent thickness and structural uniformity across very large areas (2 x 250 cm). We designed a continuous vacuum deposition system, in which the feeding and wrapping units of the system were in the open air, thanks to the specially designed fabric feedthroughs in and out of the vacuum system. The pristine fabric was fed into the oCVD vacuum reactor by unreeling from the outside atmosphere, where it was pretreated with oxidant iron(III) chloride (FeCl3) solution. The effect of rolling speed of the fabric on the structure, morphology, uniformity, and electrical conductivities of the as-deposited PEDOT films were studied. FTIR and SEM analyses were carried out to verify the structure and morphology of as-deposited PEDOT films. Uniform and conformal PEDOT films with measurable conductivity were observed independent of the rolling speed. The highest conductivity value of 803.5 S/cm was observed for the films deposited at a rolling speed of 8 cm/min and doped with Cl- ions from a 3.5 wt.% HCI solution.
Self-Powered Polyaniline/Si NIR Photodetectors for Waste Classification: Fabrication, Optimization, and Application
(American Chemical Society, 2025) Hussaini, Ali Akbar; Yilmaz, Kurtulus; Karaman, Mustafa; Yildirim, Murat
Rapid rise in the population and urbanization has led to increased waste generation, creating significant challenges for efficient waste management. Although recycling remains effective, manual sorting of diverse materials limits the scalability. In this study, we report the fabrication and optimization of polyaniline (PANI) interlayer-based photodetectors with varying film thicknesses by using plasma-enhanced chemical vapor deposition (PECVD). PANI films were characterized via UV-vis spectroscopy, FTIR, XPS, and AFM. Devices were tested under varying solar light intensities and a broad wavelength range (351-1600 nm). The photodetector with a 200 nm PANI layer exhibited the best performance, achieving a responsivity of 1.013 A/W, detectivity of 1.34 x 1011 Jones, and EQE of 114.2% under self-powered operation. We propose the use of this device for waste classification, shifting from conventional reflected NIR signal analysis to examining transmitted near-infrared (NIR) wavelengths through waste samples. Our results show that photocurrent, responsivity, and EQE from the PANI/n-Si heterojunction can reliably distinguish material types. This work demonstrates the potential of self-powered NIR photodetectors to enable automated, scalable, and efficient waste classification systems.
Synthesis of P(n-Isopropyl Acrylamide- Hydroxypropyl Methacrylate) Thermo Responsive Copolymer Films by Initiated Chemical Vapor Deposition Method
(Konya Teknik Univ, 2024) Sevgili Mercan, Emine; Yilmaz, Kurtulus; Karaman, Mustafa
This study illustrates the deposition of thermo responsive p(N-isopropyl acrylamidehydroxypropyl methacrylate) p(NIPAAm-HPMA) copolymer thin films by initiated chemical vapor deposition (iCVD) method using tert-butyl peroxide (TBPO) as the initiator. Copolymers were deposited at three different HPMA flow rates and the effects of NIPAAm/HPMA flow rate ratio on the deposition rate, structure and responsive properties of the as-deposited films were investigated. The highest deposition rate of 50 nm/min was observed for the copolymer deposited using lowest NIPAAm/HPMA monomer ratio studied. The deposition rate showed a significant increase with decreasing NIPAAm/HPMA flow ratio. Results of FTIR and XPS spectroscopy analyses revealed a significant preservation of structural retention in iCVD p(NIPAAm-HPMA) thermo-responsive films. Lower critical solution temperatures (LCST) of p(NIPAAm-HPMA) films were determined by carrying out a temperature-dependent contact angle analysis. Accordingly, it was shown that LCST was varied between 19 and 23 degree celsius, which was observed to be dependent on the NIPAAm/HPMA monomer ratio. That LCST range is considerably below the literature- reported values for pNIPAAM, which makes the as-deposited copolymer suitable for applications that require thermos-responsive properties at lower temperatures.