The structure of κ-carrageenan consists of hydroxyl groups, which enables the formation of coordinate bonds with cations or protons. κ-carrageenan has high proton conductivity, in which the protons migrate through its hydrogen-bonded network, because of its hydrophilic nature, which promotes water absorption. Other advantages, such as low energy consumption, low-cost synthesis, carbon neutrality and harmless disposal have also enhanced the potential of carrageenan as a polymer electrolyte. The films possess good transparency, tensile strength and gelling ability. The considerable amount of sulphonic groups in the structure of κ-carrageenan allows films to form through the self-aggregation of its helical structures. Ĭarrageenans are natural water-soluble linear sulphated polysaccharides extracted from red seaweed, The predominant carrageenan extracted from Eucheuma cottonii is κ-carrageenan ( Fig 1a), which consists of alternating repeating units of 4-linked 3,6-anhydro-α-D-galactose and 3-linked β-D-galactose with one sulphate per disaccharide unit. The present works uses κ-carrageenans as a polymer electrolyte due to its chemical structure, which is similar to cellulose or chitosan.Ĭarrageenans which have molecular masses ranging from 400–600 kDa, are mainly used in the food industry as gelling, thickening and stabilizing agents and and are also used in cosmetics, paints, pharmaceuticals and the biomedical industry. However, carrageenans have rarely been used as polymer electrolytes. Chitosan polymer electrolytes in salt complexes, chemically modified chitosan and chitosan blended with other polymers have been reported in the literature for application in electrochemical devices. The use of chitosan as a polymer electrolyte is noteworthy. The most widely studied polysaccharides for PEM applications are starch, cellulose and chitosan. Polysaccharides are the most abundant natural polymer in the environment. In recent years, research has extended to natural polymers due to their low- cost, availability and biocompatibility compared to synthetic polymers. Since the discovery of the first ion-conducting polymer, namely, poly(ethylene oxide) (PEO) complexed/dissolved with alkali metal salts, different types of polymers have been investigated for potential use as PEMs. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Īn important component in electrochemical devices is the polymer electrolyte membrane (PEM), which is an ion-conducting membrane with moderate-to-high ionic conductivity (≤ 10 −4 S cm -1) at room temperature. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All the relevant data are within the paper (Figures and Tables).įunding: This research work is jointly financially supported by the Ministry of Education Malaysia through the Long-term Research Grant Scheme (LRGS/2013/UKM-UKM/TP/01) and the Universiti Kebangsaan Malaysia (UKM) through the University Research Grants (GUP-2016-038). Received: JAccepted: SeptemPublished: September 28, 2017Ĭopyright: © 2017 Liew et al. PLoS ONE 12(9):Įditor: Jie Zheng, University of Akron, UNITED STATES The hydrated membranes showed a two orders of magnitude higher ionic conductivity than the dried membranes.Ĭitation: Liew JWY, Loh KS, Ahmad A, Lim KL, Wan Daud WR (2017) Synthesis and characterization of modified κ-carrageenan for enhanced proton conductivity as polymer electrolyte membrane. The ionic conductivity of κ-carrageenan and OMPC were 2.79 × 10 −6 S cm -1 and 1.54 × 10 −5 S cm -1, respectively. The characterization demonstrated that the membranes had been successfully produced. The conductivity properties of the membranes were investigated by electrochemical impedance spectroscopy (EIS). The chemical structure of OMPC samples were characterized using Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance ( 1H NMR) spectroscopy and 31P nuclear magnetic resonance ( 31P NMR) spectroscopy. The membranes were prepared by a solution casting method. New membranes were developed by chemically modifying κ-carrageenan via phosphorylation to produce O-methylene phosphonic κ-carrageenan (OMPC), which showed enhanced membrane conductivity. In general, pure κ-carrageenan membranes show a low ionic conductivity. Polymer electrolyte membranes based on the natural polymer κ-carrageenan were modified and characterized for application in electrochemical devices.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |