And Polyethylene Glycol(PEG) Complexation of Lithium Perchlorate(Liclo4)

INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 9, ISSUE 01, JANUARY 2020 ISSN 2277-8616

Transition Studies Of Polyvinylidene Fluoride(PVDF) And Polyethylene Glycol(PEG) Complexation Of Lithium Perchlorate(Liclo4)

K. Venkata Ramana, A.R. Subrahmanyam, B. Bhanu Prasad, M. Ravindar Reddy, V. Madhusudhana Reddy, M. Chandra Shekar

Abstract: An investigation is carried out on a new solid polymer electrolyte system consisting of poly vinylidene fluoride (PVDF) + poly ethylene glycol (PEG) as a host polymer. Lithium per chlorate (LiClO4) is used as a salt. Solution Casting Technique (SCT) is used to prepare the films. The films are characterized using X-ray Diffraction (XRD), Differential Scanning Calorimeter (DSC), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) and UV Spectrometers. XRD, DSC and SEM results evidenced the decrease in crystallinity of PVDF+PEG due to the presence of LiClO4.

Keywords: poly ethylene glycol(PEG)l, poly vinylidene fluoride(PVDF, LiClO4 (Salt) , solution casting technique —————————— ◆ ——————————

1. INTRODUCTION XRD patterns of the above polymers are recorded using Polymer electrolytes with suitable salts are capable materials PHILIPS PW 3710. Fourier Transform Infrared (FTIR) for electrochemical device applications, like high energy spectroscopic studies are carried out using JASCOFTIR-5300 -1 density rechargeable batteries, fuel cells, electro chromic Spectrometer over a wave number range of 500 – 4000 cm . display devices etc.,[1,2,3]. The area of polymer electrolytes Surface properties of these blended polymers are studied has gone through various developmental stages, i.e. from dry using Scanning Electron Microscope (SEM). Optical solid polymer electrolyte (SPE) systems to plasticized, gels, absorption spectra are recorded at room temperature in the composite polymer electrolytes (CPE). We recently reported range of 200 -600 nm using UV Optical Spectrometer. the characterization of PVDF solid polymer electrolyte mixed Thermal properties are studied using Differential Scanning 0 0 with LiClO4 using XRD, DSC, SEM, FTIR and UV [4]. In this Calorimetry (DSC) in the temperature range 30 C – 400 C. paper, we present the synthesis and characterization of a new solid polymer electrolyte system consisting of (PVDF) + (PEG) RESULTS AND DISCUSSION as a host polymer with Lithium per chlorate (LiClO4). The XRD Studies: prepared samples are characterized using the techniques DSC, XRD, SEM, FTIR and UV. The results are compared and discussed to explain the crystalline nature, thermal stability and optical absorption of the polymer electrolyte samples PDVF+PEG doped with different concentrations of LiClO4.

EXPERIMENTAL Solid polymer blend films based on poly vinyl(PVDF) (PEG) with LiClO4 films have been prepared by using solution casting procedure. Pure PVDF (320000MW from Sdfine), PEG(6000MW from Sdfine) and LiClO4 are added with various percentages i.e., (70:30), (70:30:5), (70:30:10), (70:30:15),

(70:30:20), (70:30:25), (70:30:30), by wt% ratio by Solution Figure 1XRD patterns of PVDF+PEG membranes with (A) Casting Technique. The Blend Polymer Electrolytes are 0% of LiClO4 ; (B) 5% of LiClO4; (C) 10% of LiClO4 ; (D) 15% dissolved in DMF: the solutions are obtained by Stirring about of LiClO4 ; (E) 20% of LiClO4 ; (F) 25% of LiClO4 and (G) 10-12 hours to get homogeneous solutions. These solutions 30% of LiClO4 are allowed to get evaporated in dishes and after 48 hours, thin films are obtained. These films are separated from the dish surface and are stored in Desiccators. Figure 1 shows the XRD patterns of PVDF+PEG membranes

______with different concentrations of LiClO4 . From Fig.1, it is clear • K. Venkata Ramana, A.R. Subrahmanyam B. Bhanu Prasad, that there is a sharp peak around 2θ=200 which is present in M. Ravindar Reddy, Department of Applied Sciences, M.V.S.R. all the samples Fig.1(A-G). This may represent a crystalline Engineering College, Nadergul, Hyderabad. • V. Madhusudhana Reddy Department of S & H, Malla Reddy phase in the amorphous matrix of the samples. From Fig1, it college of Engineering & Technology, Hyderabad. is also clear that the magnitude of crystallinity decreases with

• M. Chandra Shekar Department of Physics, JNT University, increase in the concentration of LiClO4 in PVDF+PEG and Hyderabad. there is no evidence of new peaks in the diffraction pattern this

is due to low moleculer weight of PEG& LiClO4 . [8].In the pure PVDF+PEG sample, the small peaks in addition to the sharp

peak indicate the partial crystalline nature of the sample (Fig.1A). DSC Studies:

Figure 2 DSC plots of PVDF+PEG membranes with (A) 0% of LiClO4 ; (B) 5% of LiClO4; (C) 10% of LiClO4 ; (D) 15% of LiClO4 ; (E) 20% of LiClO4 ; (F) 25% of LiClO4 and (G) 30% of LiClO4

As shown in Fig. 2, in DSC plots of PVDF+PEG+LiClO4 with different percentages of LiClO4 in PVDF+PEG, there is a small endothermic dip around 1750C, which persists in all concentrations of LiClO4 in PVDF+PEG Fig. 2(B-G). This dip is observed even in pure PVDF+PEG (Fig.2A). A broad exothermic peak is observed around 3000C, which persists in all concentrations of LiClO4 in PVDF+PEG, Fig.2(B-G) FIGURE 3 The surface morphology, characterised by SEM, of except for pure PVDF+PEG (Fig.2A). The peak position is PVDF+PEG membran es with (A) 0% of LiClO4 ; (B) 5% of slightly changing with the concentration of LiClO4 in LiClO4; (C) 10% of LiClO4 ; (D) 15% of LiClO4 ; (E) 20% of PVDF+PEG. The position of Tp shifts towards higher LiClO4 ; (F) 25% of LiClO4 and (G) 30% of LiClO4 temperatures with increase in the concentration of LiClO4 in PVDF+PEG, Fig.2(B-G). For pure PVDF+PEG the exothermic peak is absent. The surface morphology of PVDF+PEG and PVDF+PEG+LiClO4 polymer systems is observed using SEM. Thus, Fig. 3 shows the surface structure of PVDF+PEG and PVDF+PEG+LiClO4 polymer systems with different concentrations of LiClO4 in PVDF+PEG. From Fig. 3, it is clear that the surface of PVDF+PEG film appears to be semi crystalline which is also confirmed by XRD studies on these films. As in Fig.3, increase in the concentration of LiClO4 in PVDF+PEG decreases the degree of crystallinity in the samples which is supported by XRD studies on the same samples.

electrolyte indicates the influence of LiClO4 on PVDF+PEG for better conducting properties.

FIGURE 4 The FTIR spectra of PVDF+PEG membranes with(A) 0% of LiClO4 ; (B) 5% of LiClO4; (C) 10% of LiClO4 ; (D) 15% of LiClO4 ; (E) 20% of LiClO4 ; (F) 25% of LiClO4 and (G) 30% of LiClO4

Figure 4 shows the FTIR spectra of PVDF+PEG with different concentrations of LiClO4. As in Fig.4, strong growth in the CF2 stretching in FTIR with increasing concentratration of lithium salt implies the acid–base complexation of − PVDF+PEG with lithium. However, the ClO4 absorption indicated the presence of both free and ion-paired structure in (PVDF+PEG)/LiClO4 film. As in Fig.4, the intensity of the alibhatic C-H scattering vibration bands are observed in FTIR spectra of PVDF+PEG and PVDF+PEG+LiClO4. Using these polymer blend electrolytes electrochemical cells can be fabricated and their discharge characteristics can be studied. UV STUDIES:

FIGURE 6 (αhʋ)2 vs. hʋ plots of PVDF+PEG membranes with (a) 0% of LiClO4 ; (b) 5% of LiClO4; (c) 10% of LiClO4 ; (d) 15% of LiClO4 ; (e) 20% of LiClO4 ; (f) 25% of LiClO4 (g) 30% of LiClO4

Table 1 The direct band gap values of PVDF+PEG+LiClO4 electrolytes for different concentrations of LiClO4

Polymer Directbandgap(eV FIGURE 5UV absorption spectra of PVDF+PEG membranes with (A) 0% of LiClO4 ; (B) 5% of LiClO4; (C) PurePVDF+PEG(70:30) 3.46 10% of LiClO4 ; (D) 15% of LiClO4 ; (E) 20% of LiClO4 ; (F) 25% of LiClO4 and (G) 30% of LiClO4 PVDF+PEG+LiClO4(70:30:05) 3.35

PVDF+PEG+LiClO4(70:30:10) 3.44 Optical absorption spectra are recorded at room temperature PVDF+PEG+LiClO4(70:30:15) 3.44 in the range 200 – 600 nm using Optical Spectrometer. Near PVDF+PEG+LiClO4(70:30:20) 3.43 fundamental band edge, direct band transitions may occur PVDF+PEG+LiClO4(70:30:25) 3.43

[6,7]. Thus, considering α as absorption coefficient, h as PVDF+PEG+LiClO4(70:30:30) 3.43 Planck’s constant, υ as frequency of incident light and hυ as 2 the photon energy, (αhυ) versus hυ can be plotted as shown CONCLUSIONS in Fig. 6. The direct band gap values of PVDF+PEG, DSC studies showed that in the DSC plot of PVDF+PEG+ PVDF+PEG+different concentrations of LiClO4 are tabulated LiClO4 electrolyte polymers, there is an exothermic peak in Table 1. From Table 1, the band gap of PVDF+PEG polymer observed which slightly shifts due to the addition of LiClO4 to electrolyte is 3.46 eV. Addition of different concentrations of PVDF+PEG. DSC, XRD and SEM studies indicate the LiClO4 to PVDF+PEG reduced the band gap. Hence, decrease of crystallinity of PVDF+PEG electrolyte with conductivity of PVDF+PEG+LiClO4 increase. Thus, the direct increase in the concentration of LiClO4 . The complexation of band gap values of PVDF+PEG+ LiClO4 (70:30:30) polymer PVDF+PEG polymer with LiClO4 has been confirmed using 2609 IJSTR©2020 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 9, ISSUE 01, JANUARY 2020 ISSN 2277-8616

XRD and FTIR spectra. The direct band gap values of PVDF+PEG+LiClO4 polymer electrolytes indicate the influence of LiClO4 on PVDF+PEG for better conducting properties. Based on these electrolytes, a high density polymer battery can be fabricated with the configuration anode/polymer electrolyte/cathode.

REFERENCES [1] T. D. Kusworo, Wibowo, A. I. Budiyono, G. D. Harjanto, A. D. Yudisthira and F. B Iswanto, J. Appl. Sci. Eng. Technol. 7 (2013) 3852 [2] A. P. E. Velez, C. Torras, J. Pagan and A. Ibarz, Food Engg. Rev. 3 (2011) 136 [3] C. A. Fuenmayor, S. M. Lemma, S. Mannino, T. Mimmo and M. Scampicchio, J. Food Engg. 122 (2014) 110 [4] K.Venkata Ramana M. Chandra Shekar A.R.Subrahmanyam, M.Ravindar Reddy and V. Madhusudhana Reddy Int. J. Emer. Tech. Adv. Engg. 7 (2017) 484 and references therein. [5] D.S. Davis and T.S. Shalliday, Phys.Rev.118 (1960) 1020 [6] G.M. Thutupalli and J. Tomlin, J. Phy. D: Appl. Phy. 9 (1976) 1639 [7] Structural and ionic conductivity of PEO bled PEG Solid Polymer Electrolyte.M.JaipalReddy et al/Solid state Ionics 177(2006) 253-256.