Person: DÜZYER GEBİZLİ, ŞEBNEM
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DÜZYER GEBİZLİ
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ŞEBNEM
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Publication Reversible thermochromic polycaprolactone nanofibers for repetitive usage(Korean Fiber Soc, 2023-08-28) Gebizli, Şebnem Düzyer; DÜZYER GEBİZLİ, ŞEBNEM; TEZEL, SERKAN; Güçlü, Nihal; Tiritoglu, Mehmet; TİRİTOĞLU, MEHMET; Tezel, Serkan; Orhan, Mehmet; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Otomotiv Mühendisliği/ Polimer Malzemeler Anabilim Dalı.; 0000-0003-3737-5896; 0000-0001-8043-4148; C-5123-2013; AFO-0698-2022; AAG-8034-2021Color change technology offers unique and challenging opportunities. Thermo-responsive color-changing nanofibers with reversibility have great potential as thermal sensors due to their increased sensitivity and fast response. Herein, polycaprolactone (PCL) nanofibers were produced by adding a leuco-based thermochromic dye with various concentrations (1%, 3%, and 5% wt corresponding to PCL1, PCL3, and PCL5, respectively). The color-changing properties with repetitive heating and cooling were studied, and the effect of dye concentration on the nanofiber properties was determined. The surface properties, dye presence, thermal and mechanical properties were analyzed by SEM-EDS, FTIR, DSC, and tensile tests. Finally, the color change properties were monitored by 1000 heating and cooling cycles between 20 and 40 & DEG;C. Thermochromic PCL nanofibers were successfully produced by electrospinning. However, some agglomerates were observed on the nanofibers with increasing dye concentration in SEM images. It was seen that the optimum dye concentration was 3% in terms of the electrospinnability. For PCL5, both presence of carbon, oxygen, nitrogen, and fluorine in EDS spectra, the shifted peaks at 2917 and 2849 cm-1, and the new peaks at 1558, 1517, 1330, 1274, 1213 and 883 cm-1 in FTIR spectra confirmed that dye had been successfully incorporated into the PCL structure. The dye addition caused a decrease in the crystallization degrees, which resulted in lower mechanical properties. PCL5 had the lowest modulus. Color measurements showed that 1% of dyes concentration was not sufficient for the thermochromic property, and the color change was still visually detectable for PCL3 and PCL5 even after 1000 heating and cooling cycles. Color change activation temperature (TA) was confirmed between 30 and 32 & DEG;C, and the stability of color change was confirmed for 1000 heating and cooling cycles. After 1000 heating and cooling cycles, the color change was still detectable for PCL3 and PCL5. Consequently, this study showed that reversible thermochromic PCL nanofibers could be promising materials for future sensor applications.Publication Silymarin-loaded electrospun polycaprolactone nanofibers as wound dressing(Springer Heidelberg, 2023-03-02) Sali, Aisegkioul; Gebizli, Şebnem Düzyer; Göktalay, Gökhan; Sali, Aisegkioul; DÜZYER GEBİZLİ, ŞEBNEM; GÖKTALAY, GÖKHAN; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Biyomalzeme Bölümü.; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Farmakoloji Anabilim Dalı.; 0000-0003-3737-5896; 0000-0001-6261-4233; 0000-0002-1973-5344; AAH-1448-2021; AFO-0698-2022; HTA-7306-2023Herein, we fabricated silymarin (SIL)-loaded polycaprolactone (PCL) electrospun nanofiber mats containing different SIL concentrations (5, 7.5, 10%) for wound dressing applications. Solution properties, nanofiber properties and SIL presence were analyzed by viscosity measurements, SEM and FTIR, respectively. Solution viscosities were increased with increasing SIL concentrations resulting in bead-free, thicker and smooth nanofibers. The lowest contact angle was measured as similar to 92 degrees for 10% SIL-loaded sample which had the smoothest nanofibers and a more controlled and continuous SIL release with a rate of 68.29% at end of 144 h during in vitro release experiments. In vivo studies on rats were conducted on this sample and results were compared with a conventional wound dressing and a PCL nanofiber mat. In comparison, the 10% SIL-loaded sample provided more rapid and significantly greater wound healing from the first day of observation. The results confirmed the potential application of PCL/SIL electrospun nanofiber mats as wound dressing.Publication Effect of deposition time on the optoelectrical properties of electrospun PAN/AgNO3 nanofibers(Ege Universitesi, 2020-01-01) Gebizli, Şebnem Düzyer; DÜZYER GEBİZLİ, ŞEBNEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.The aim of this study is to produce optically transparent nanofibers with adequate electrical conductivity for optoelectrical applications where transparency and conductivity are needed. Therefore, conductive polyacrylonitrile/silver nitrate (PAN/AgNO3) nanofibers were produced by electrospinning with different deposition times ranging from 1 minute to 10 minutes. The effect of deposition time on the sheet resistance and optical transparency of the nanofibers were investigated. The surface characteristics, electrical properties and transmittance values of the electrospun mats were evaluated. Nanofibers with diameters under 700 nm were obtained. With the increasing deposition time, the sheet resistance and transparency of the samples were decreased. In order to figure out the optimum deposition time, the figures of merit of the samples were calculated. The figures of merit of the samples showed that the sample deposited for three minutes gave the best performance among the others. It was seen that conductive PAN/AgNO3 nanofibers are promising for optoelectrical applications.Publication A new approach to determination of the instability of air-jet textured yarns(Inda, 2015-01-01) Koç, Serpil Koral; Düzyer, Şebnem; Hockenberger, Aslı; KORAL KOÇ, SERPİL; DÜZYER GEBİZLİ, ŞEBNEM; HOCKENBERGER, ASLI; Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü; 0000-0002-0739-8256; 0000-0003-3737-5896; AFZ-8325-2022; AFO-0698-2022; IMR-3897-2023Determination of the instability of air-jet textured yarns is a very important aspect of their quality characterization. To overcome this problem many researchers have suggested different techniques, however none has been accepted as a standard method. Among all the methods, that suggested by Demir et al. takes attention, since it was improved after investigating the advantages and disadvantages of most of the techniques in use. Recovery from strain measurements are commonly used to get information about fiber molecular structure. In this study, instability of air-jet textured yarns was investigated by using both Demir's instability test method and recovery from strain measurements. It was observed that Demir's method is a practical and reliable way to compare the instability of air-jet textured yarns produced from the same raw material. For comparing different materials it was more beneficial to use recovery from strain measurements.Publication Influence of solvent system on the optoelectrical properties of pcl/carbon black nanofibers(Taylor & Francis Inc, 2022-01-04) Peksöz, Ahmet; PEKSÖZ, AHMET; Gebizli, Şebnem Düzyer; DÜZYER GEBİZLİ, ŞEBNEM; Cunayev, Şaban; Tezel, Serkan; TEZEL, SERKAN; Koç, Serpil Koral; KORAL KOÇ, SERPİL; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; 0000-0003-3737-5896; 0000-0002-0739-8256; AFZ-8325-2022; C-5123-2013; AFO-0698-2022In this study, conductive and transparent polycaprolactone (PCL)/carbon black (CB) nanofibers are produced by electrospinning. In order to investigate the effect of solvent system on the optoelectrical properties of PCL/CB nanofibers, the fibers are produced from two different solvent systems; namely, chloroform (CHL) and dimetyl formamid (DMF). For optoelectrical characterization, nanofibers are produced with different deposition times in the range of 1-10 minutes. Surface, optical, electrical and optoelectrical properties of the PCL/CB nanofibers are evaluated. Nanofibers produced from CHL solvent system results in non-uniform nanofibers with higher diameters. They also give a larger diameter distribution. On the other hand, nanofibers with uniform and smaller diameters are obtained from DMF system. UV-spectrophotometer analysis show that nanofiber mats produced from both solvent systems have similar optical transparencies. Lower sheet resistance values are obtained with the nanofiber mats produced from DMF system according to electrical characterizations. Higher Figure of Merit values are calculated for the nanofiber mats produced in DMF solvent system. Considering all the results, it can be concluded that PCL/CB nanofibers produced from DMF solvent system are better candidates compared to the nanofibers produced from CHL solvent system for optoelectrical applications.Publication Development of polycaprolactone-based electrospun ph-sensitive sensors as instant colorimetric indicators for food packaging(Wiley, 2023-06-01) Güçlü, Nihal; Düzyer Gebizli, Şebnem; DÜZYER GEBİZLİ, ŞEBNEM; Orhan, Mehmet; ORHAN, MEHMET; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; 0000-0003-3737-5896; 0000-0001-8043-4148; AAG-8034-2021; AFO-0698-2022In the present study, polycaprolactone/polyethylene glycol (PCL/PEG) electrospun nanofibres with different anthocyanin (1%, 2%, 3%, and 5%) were fabricated for the instant measurement of pH, especially for applications-such as food freshness detection-where quick response is required. The solution, surface, chemical, thermal, wettability, mechanical, and release properties of the samples were evaluated by viscosity measurements, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), contact angle measurements, and tensile tests, respectively. The colorimetric analyses were also investigated against the solutions at different pH values and bacterial solutions. Finally, the on-site performance of the sensor was evaluated. Anthocyanin addition initially lowered the solution viscosity, resulting in thinner fibres with a diameter of 288 nm. The diameters were increased up to 395 nm with the increasing anthocyanin. Anthocyanin addition enhanced the wettability and the mechanical properties, and the contact angles decreased to 43 degrees. The highest modulus was observed for 1% anthocyanin, with a value of 6.162. The release experiments revealed that the anthocyanin-loaded samples released a large amount of anthocyanin (between similar to 12% and 38%) in the first 15 s. The colorimetric analyses showed that PCL/PEG nanofibre mats with 2% and 3% anthocyanin concentrations were the most capable pH-sensitive sensors for detecting pH changes from 2 to 8. As a result, it can be concluded that 3% anthocyanin is the threshold value for the production of the anthocyanin-loaded nanofibre mats, and these structures are promising for the instant detection of pH proved by the on-site application.Publication Copper-electroplating of biodegradable pcl nanofiber mats(E.u. Printing And Publishing House, 2023-01-01) Tezel, Serkan; TEZEL, SERKAN; Gebizli, Şebnem Düzyer; DÜZYER GEBİZLİ, ŞEBNEM; Jadouh, Ahd; KORAL KOÇ, SERPİL; Peksöz, Ahmet; PEKSÖZ, AHMET; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-3737-5896; 0000-0002-0739-8256; C-5123-2013; AFZ-8325-2022; AFO-0698-2022In this study, biodegradable polycaprolactone (PCL) nanofibers were copper (Cu) electroplated in a more environmentally friendly bath compared to conventional electroplating baths. The Cu-plating mechanism and determination of the optimum parameters for the production of Cu-plated PCL nanofiber mats were explained. PCL nanofibers were produced on metal frames by electrospinning. Cu-electroplating needs a conductive surface. To provide this, a gold/palladium (Au/Pd) mixing was sputtered on the PCL samples with different sputtering thicknesses (1-5-10-15 and 20 nm). After determining the minimum sputtering thickness as 5 nm, the samples were Cu-plated for 1, 3, 5, and 30 minutes in a citric acid electroplating bath. The surface properties of the samples were evaluated after Au/Pd sputtering and electroplating, respectively. Elemental analyses, mapping, and electrical characterizations were also performed after electroplating. After Au/Pd sputtering, the SEM images showed that randomly aligned nanofibers with an average diameter of 223 nm were produced. After electroplating, the average nanofiber diameters increased up to 444 nm. It was seen that the coating grew along the surface of the single nanofibers indicating a smooth Cu coating. While elemental analyses presented a Cu content of 79.77%, electrical characterizations gave a sheet resistance value of 5.98 m Omega/sq for the samples Cu-plated for 30 minutes, indicating a highly conductive structure. Every step of the study is described in detail to provide insight for further studies.Publication Different methods of fabricating conductive nanofibers(Ege Univ, 2019-01-01) Düzyer, Şebnem; DÜZYER GEBİZLİ, ŞEBNEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; 0000-0003-3737-5896; AFO-0698-2022Conductive nanofibers can be produced by different methods. In this study, four different methods to fabricate conductive nanofibers were explained and supported with experimental results. Nanofibers were made conductive by fabricating nanofibers from intrinsically conductive polymers (polyaniline/polyethylene oxide nanofiber production), coating the non-conductive nanofiber mat with a conductive material (copper electroplating of polyacrylonitrile nanofibers), adding a conducting material (carbon black nanoparticles, silver nanoparticles, ionic liquid) into the spinning solution, and heat treatment of the nanofiber mat (carbon and ITO nanofiber production). The surface and the electrical properties of the nanofibers were investigated. The advantages and disadvantages of the methods were discussed in detail. The results showed that conductive nanofibers can be successfully produced with different electrical conductivities depending on the method and the material.