Investigation of the water states of poly(styrene sulfonic acid) grafted poly(ethylene-co-tetrafluoroethylene) copolymer using FT-IR analysis

Authors

  • Tran Trong Hieu Dinh Physics Laboratory, Le Thanh Ton High School, Ho Chi Minh city
  • Hoang Hao Lam University of Science, Vietnam National University, Ho Chi Minh city
  • Thanh Danh Tran University of Science, Vietnam National University, Ho Chi Minh city
  • Quang Luan Le Biotechnology Center of Ho Chi Minh city
  • Van Man Tran University of Science, Vietnam National University, Ho Chi Minh city
  • Truc Phuong Huynh University of Science, Vietnam National University, Ho Chi Minh city
  • Van Phuc Dinh Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh city
  • Anh Tuyen Luu Center for Nuclear Technologies, Vietnam Atomic Energy Institute, Ho Chi Minh city
  • Kim Ngoc Pham University of Science, Vietnam National University, Ho Chi Minh city
  • Duy Tap Tran University of Science, Vietnam National University, Ho Chi Minh city

Keywords:

ETFE, FT-IR, pre-irradiation grafting, water states

Abstract

The water states of poly(styrene sulfonic acid) (PSSA) grafted poly(ethylene-co-tetrafluoroethylene) copolymers (ETFE-PEMs) with grafting degree (GD)=8.8-30.5% are investigated under ambient conditions by using FTIR analysis. Detailed analysis of the FT-IR spectra of ETFE-PEMs allows the observation of each component of water in the two broad bands of 1500-2000 cm-1 and 2400-3800 cm-1. These components include protonated water (H3O+…(H2O)n), H-bonded water to sulfonic acid groups ((SO3)…(H3O+)(H2O)n), H-bonded water to other water molecules ((H2O)…(H2O)), and non-H-bonded water (HOH…F). Of these water forms, ((SO3)…(H3O+)(H2O)n) is predominantly represented. Free water (non-H-bonded water) is assumed to be trapped in the holes of the ETFE backbone and is thus difficult to remove at 50oC over a 24 h period. The total peak areas of the water molecules significantly increase with GD indicating that the ETFE-PEM with higher GD possesses higher water content. Moreover, the increase of the total peak area with GD via two steps reveals an interesting relationship between the hierarchical structures and the capacity of water content under ambient conditions. The observed water content at ambient conditions can significantly affect the conductance of ETFE-PEMs under conditions of low relative humidity such as during fuel cell operation or measurement procedures of specific characterisations or testing methods.

DOI:

https://doi.org/10.31276/VJSTE.64(2).03-09

Classification number

2.1

Downloads

Published

2022-06-15

Received 19 April 2021; accepted 24 June 2021

How to Cite

Tran Trong Hieu Dinh, Hoang Hao Lam, Thanh Danh Tran, Quang Luan Le, Van Man Tran, Truc Phuong Huynh, Van Phuc Dinh, Anh Tuyen Luu, Kim Ngoc Pham, & Duy Tap Tran. (2022). Investigation of the water states of poly(styrene sulfonic acid) grafted poly(ethylene-co-tetrafluoroethylene) copolymer using FT-IR analysis. Vietnam Journal of Science, Technology and Engineering, 64(2), 3-9. https://doi.org/10.31276/VJSTE.64(2).03-09

Issue

Section

Physical Sciences