Akademik Veri Yönetim Sistemi
3 rd International Conference on Applied Engineering and Natural Sciences, Konya, Türkiye, 20 - 23 Temmuz 2022, ss.2008
Halochromic dyes can be defined as dyes which show chromic behavior when the pH changes. Depending on their hypsochromic or hyperochromic shift upon (de)protonation, they are classified as negative and positive pH-sensitive dyes. These structures can be used as pH-sensors for the indication of hazardous environments, monitoring food freshness or wound healing.
With their small diameters, high surface area per volume, small pore size and high porosity, nanofibers hold great potential for halochromic sensor applications. Moreover, they can improve the halochromic sensor’s properties, such as response time and sensitivity. Among many nanofiber production methods, electrospinning is the most preferable and effective method for producing nanofibers from polymer solutions. Due to the flexibility of the method, halochromic dyes can also be incorporated into the nanofiber structure.
Although electrospinning is a relatively simple method to produce such structures, many parameters affect the process and the final product. Mainly, the solution properties directly affect the process and the nanofiber structure. Therefore, the relationship between the solution and the structure should be investigated comprehensively.
In this study, halochromic dye added polyacrylonitrile (PAN) nanofibers were produced by electrospinning. PAN was chosen because of its good mechanical strength, stability, low-cost and ease of spinnability in electrospinning. Later, the effects of solution parameters on the electrospinning and nanofiber properties were studied. For this purpose, two different polymer solutions (8% wt. PAN and 8% wt.PAN+3% wt. halochromic dye) were prepared and then characterized in terms of viscosity, pH and surface tension. Afterwards, electrospinning was performed, and the surface properties of the samples were investigated by an optical microscope. After adding the halochromic dye into the polymer solution, its surface tension and pH values decreased from 31.81 mN/m to 28.80 mN/m, from 7.12 to 6.23, respectively. The dye addition inherently resulted in higher viscosity (from 1363 to 1754 cP), which led to difficulties and higher nanofiber diameters during electrospinning. Optical microscopy images revealed that halochromic dye was successfully integrated into the nanofiber structure. This study demonstrates that electrospinning allows the production of halochromic dye added PAN nanofibers and these structures can be evaluated for pH-sensing applications.