Fabrication and characterization of poly(vinyl alcohol)—Glycerol—Spinel ferrites flexible membranes Adel Shaheen, 1 Mohammad A. Haija, 2 Mariem Chamakh, 3 Ghada A. I. Assayed, 1 Fawzi Banat, 4 Ahmad I. Ayesh 3,5 1 Physics Department, Hashemite University, Zarqa, Jordan 2 Department of Chemistry, Khalifa University, Abu Dhabi, United Arab Emirates 3 Department of Mathematics, Statistics and Physics, Qatar University, Doha, Qatar 4 Department of Chemical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates 5 Center for Sustainable Development, Qatar University, Doha, Qatar Correspondence to: A. I. Ayesh (E-mail: ayesh@qu.edu.qa) ABSTRACT: Polymer membranes of ferrites nanoparticles, glycerol, and poly(vinyl alcohol) (PVA) were fabricated using a solution cast- ing method. Spinel ferrites nanoparticles, CuFe 2 O 4 or ZnFe 2 O 4 , and glycerol were used as dopants to control the membranes’ electrical conductivity. The morphology, composition, and interaction between PVA and the dopants were investigated byscanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differentialscanning calorimeter (DSC), and thermal gravimetric analysis (TGA). Electrical characterization of the membranes was conducted by impedance spectroscopy using frequencies between 1 and 10 6 Hz and variable temperatures. The results revealed a negative temperature coefficient of the resistance of the membranes. Additionally, membranes with ZnFe 2 O 4 nanoparticles exhibit higher electrical impedance than those with CuFe 2 O 4 nanoparticles. Therefore, electrical conductivity could be controlled using a suitable dopant’s composition and concentration. The membranes pres- ented in this study exhibit semiconducting properties, thus, they have potentials to be utilized in multiple applications including the flexible organic-based device. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48821. KEYWORDS: composites; nanoparticles; nanowires and nanocrystals; structure-property relationships; synthesis and processing tech- niques; thermogravimetric analysis (TGA) Received 27 May 2019; accepted 5 December 2019 DOI: 10.1002/app.48821 INTRODUCTION Poly(vinyl alcohol) (PVA) is a water-soluble synthetic polymer that is formed from a hydrolysis process of poly(vinylacetate). 1 It has high chain flexibility as well as high concentration for the polar gro- upsaccording to the polymer’s molar mass. PVA is typically mixed with natural polymers to produce biodegradable blends because of its water solubility and thin film forming characteristics. PVA hydrogels are often utilized for biomedical applications because of their biocompatibility, superior adhesion, and blending characteris- tics. 2,3 Nevertheless, PVA is a proton conducting material with low conductivity, 4 hence, its electrical conductivity should be enhanced in order to be utilized for device applications including bio- implantable devices. 5 Ionic liquids (IL) are frequently utilized as a dopant for PVA due to their high electrical conductivity as well as many excellent features that include non-flammability, thermal sta- bility, high ionic conductivity, as well as non-volatility. Furthermore, the addition of IL to PVA allows the control of its electrical conduc- tivity, improve membranes’ flexibility, and increases its toughness. 6 The blending of PVA with nanoparticles enables the production of custom-design composite membranes that can be utilized for prac- tical applications. The properties of the membranes can be engineered by a thorough selection of nanoparticles’ type, size, shape, concentration within the membranes, and so forth. 7 Herein, PVA represents a flexible matrix that holds the nanoparticles, while their fascinating features remain accessible. 8 This approach enables the recycling of nanoparticles since PVA is water soluble. Thus, the nanoparticles can be retrieved from the membranes and utilized for further application cycles. 9 Accordingly, PVA-based membranes can be used for multiple cycles of flexible device applications. 7,8,10,11 Electrical impedance spectroscopy is normally utilized to acquire an insight into polymer membranes including electrical © 2019 Wiley Periodicals, Inc. 48821 (1 of 8) J. APPL. POLYM. SCI. 2019, DOI: 10.1002/APP.48821