Linking interfacial energies with proton conductivity in sulfonated poly (ether ether ketone) nanocomposite. (16th September 2021)

• Record Type: Journal Article
• Authors: Esmaeilzadeh, Zahra; Karimi, Mohammad; Shoushtari, Ahmad Mousavi; Javanbakht, Mehran
• Is Part Of: Polymer. Volume 230(2021)
• Publication Date: 2021-09-16
• Subjects: Interfacial energy -- Proton conductivity -- Surface free energy -- Multi-walled carbon nanotube -- Proton exchange membrane -- Polydopamine; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.124067
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: So far, numerous studies have been conducted to enhance the proton conductivity of sulfonated poly (ether ether ketone) (SPEEK) as a proton exchange membrane (PEM) by incorporating nanofillers. However, the role of the filler-matrix interface in the proton conduction process has been inadequately understood. Herein, the SPEEK nanocomposite of polydopamine coated multi-walled carbon nanotube (P@MWCNT) was successfully fabricated and characterized by field emission electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR). The physicochemical properties revealed that the dimensional stability of nanocomposite was improved by 32% compared to the SPEEK due to lower water uptake. Moreover, the proton conductivity of SPEEK was significantly enhanced to 0.064 S cm −1 by adding 3.5% of P@MWCNTs. The contribution of the interface of P@MWCNT-SPEEK to proton conduction was explored through an innovative approach based on the interfacial energies. By polydopamine modification, the surface free energy (SFE) of nanotubes increased from 23.6 mJ/m 2 to 29.4 mJ/m 2, and the interfacial energy of SPEEK-P@MWCNT augmented by 192%. These findings suggest that due to the increase of interfacial energy between the P@MWCNTs and polymer chains, the transfer of protons along with the interface region of nanofiller and matrix is an acceptable mechanism. Graphical abstract: Image 1 Highlights: The nanocomposite of SPEEK/polydopamine coated MWCNT was prepared. The physicochemical properties and especially the proton conductivity were improved. The role of interfacial energy in proton conduction was explored. The interfacial energy of SPEEK/nanotube increased to 17.4 mJ/m 2 by PDA coating. The proton conduction along the surface of the modified nanotubes was evidenced.