Tailoring poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) microstructure and physicochemical properties by exploring its binary phase diagram with dimethylformamide. Issue 11 (4th March 2015)

• Record Type: Journal Article
• Authors: Sousa, Ricardo E.; Ferreira, José Carlos C.; Costa, Carlos. M.; Machado, Ana V.; Silva, Maria M.; Lanceros‐Mendez, Senentxu
• Is Part Of: Journal of polymer science. Volume 53:Issue 11(2015:Jun. 01)
• Page Start: 761
• Page End: 773
• Publication Date: 2015-03-04
• Subjects: membranes -- phase diagrams -- fluoropolymers; 547
• DOI: 10.1002/polb.23692
• Languages: English
• ISSNs: 0887-6266

Abstract

ABSTRACT: Poly(vinylidene fluoride‐ co ‐chlorotrifluoroethylene) (PVDF‐CTFE) membranes were prepared by solvent casting from dimethylformamide (DMF). The preparation conditions involved a systematic variation of polymer/solvent ratio and solvent evaporation temperature. The microstructural variations of the PVDF‐CTFE membranes depend on the different regions of the PVDF‐CTFE/DMF phase diagram, explained by the Flory‐Huggins theory. The effect of the polymer/solvent ratio and solvent evaporation temperature on the morphology, degree of porosity, β phase content, degree of crystallinity, mechanical, dielectric, and piezoelectric properties of the PVDF‐CTFE polymer were evaluated. In this binary system, the porous microstructure is attributed to a spinodal decomposition of the liquid‐liquid phase separation. For a given polymer/solvent ratio, 20wt %, and higher evaporation solvent temperature, theβ phase content is around 82% and the piezoelectric coefficient, d 33, is− 4 pC/N © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2015, 53, 761–773 Abstract : Poly(vinylidene fluoride‐ co ‐chlorotrifluoroethylene) (PVDF‐CTFE) membranes are used in different applications such as sensors, actuators, and battery separators. In this work, the variations of its microstructure have been investigated as a function of polymer concentration and evaporation solvent temperature. These microstructures are correlated through the phase diagrams for the binary system (PVDF‐CTFE/DMF system) obtained by the Flory‐Huggins theory. For PVDF‐CTFE membranes, the β‐phase content, thermal and mechanical properties depend on the initial polymer concentration and solvent evaporation temperature.