Influence of Molecular Weight on the Morphology and Structure of Electrospun Polyvinylidene Fluoride (PVDF) Aminatul Sobirah Zahari 1,a , Muhammad Hafiz Mazwir 1,b* and Izan Izwan Misnon 1, c 1 Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Kuantan, Pahang, Malaysia; a amiezahari@yahoo.com, b muhammadhafiz@ump.edu.my, c eizwan@ump.edu.my, Keywords: Polyvinylidene fluoride; molecular weight; electrospinning Abstract. Polyvinylidene fluoride (PVDF) reveals outstanding properties such as lightweight, high flexibility and temperature independence material compared to other polymers. In this study, PVDF as a function of molecular weight was prepared by using an electrospinning method in order to study the influences of the molecular weight of the PVDF membrane on the morphology. Analytical techniques such as field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD) were used to characterize the electrospun PVDF membranes. FESEM was used for morphology characterization and also to measure the diameter of fibers while XRD and FTIR were employed to examine crystalline phase membranes. The lowest molecular weight has the smallest average diameter of fibers. Besides, a combination of both α-phase and β- phase crystalline was showed by XRD and FTIR results. This is because the crystalline phases and membrane morphology depend on the polymer molecular weight. In this research, it was found that the largest β-phase fraction for the electrospun PVDF membrane is 80.25 % with a molecular weight at 180,000 g/mol. Introduction For the previous decades, a tremendous increase in the usage of PVDF membrane for several applications such as in some biomedical materials, electrical components and filtration membranes [1, 2, 3]. PVDF has been widely analyzed as it comes by with high flexibility, lightweight and temperature independence material. PVDF is a semi-crystalline polymer with five well-known crystalline phases which are α, β, γ, δ and ε phases. Among all the five crystalline phases, PVDF tends to produce α-phase, β-phase and γ- phase. The α-phase is a regular crystalline phase that is found in a PVDF melt while the γ phase does not form except at high temperatures and pressures. Besides, the β-phase PVDF is obtained by methods poling or annealing at very high pressure. However, the β-phase exhibits great electrical characteristics including piezoelectric, pyroelectric and ferroelectric properties [4]. Therefore, many researches work on change α-phase to β-phase crystalline or directly produce β- phase. Based on the previous study, PVDF membrane was successfully prepared by using electrospinning method which in turn increased the formation of β-phase [5]. Nevertheless, important to assess of PVDF`s internal features as with molecular weight and crystal structure. The polymer`s molecular weight also has an impact on the deformation and flow of polymer solution as well as on the dissolution of a polymer in the solvent at a temperature [6]. Thus, PVDF have been developed using various method with different molecular weight for numerous applications. For example, Haponska et al. [7] were prepared PVDF by the immersion precipitation method while Zhao et al. [8] synthesized PVDF through a solution casting method and a quenching treatment. In this work, PVDF with different molecular weight by using electrospinning was studied. The effects of molecular weight on membrane morphology and structure were investigated. Materials Science Forum Submitted: 2020-07-27 ISSN: 1662-9752, Vol. 1025, pp 293-298 Revised: 2020-10-11 doi:10.4028/www.scientific.net/MSF.1025.293 Accepted: 2020-10-11 © 2021 Trans Tech Publications Ltd, Switzerland Online: 2021-03-30 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications Ltd, www.scientific.net. (#562754807-30/06/21,10:05:43)