Ionic liquid embedded polyimides with ultra-foldability, ultra-flexibility, ultra-processability and superior optical transparency. (26th September 2018)

• Record Type: Journal Article
• Authors: Li, Ning-Bo; Wang, Meng; Guo, Ling-Xiang; Lin, Bao-Ping; Yang, Hong
• Is Part Of: Polymer. Volume 153(2018)
• Page Start: 538
• Page End: 547
• Publication Date: 2018-09-26
• Subjects: Polyimide -- Ionic liquid -- Composite -- Optical transparency -- Flexibility; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2018.08.048
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: New generation spacecraft technology requires more and more deployable, light-weight, thin polymer films, in particular novel polyimide materials with high optical transparency, excellent foldability and superior flexibility. In this work, we develop a highly transparent, ultra-foldable, ultra-flexible and ultra-processable polyimide composite material by incorporating 5–8 wt% of ionic liquid 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide into colorless polyimide matrices. This 23-μm-thick polyimide composite film exhibits a high optical transmittance of 90.4% even at 450 nm wavelength and an incredibly low cutoff wavelength of 273 nm. It is an extremely strong and flexible material, with a tensile modulus of 844.6 MPa, a tensile strength of 48.2 MPa, a high elongation at break of 108.4%, and an extraordinary minimum bend radius of 1 μ m. It can be easily folded in half 4 times or twisted by 900° without any crack damages. Moreover, it has a low expense cost and good film processability for industrialization manufacturing. All of these superior performances render this ionic liquid/polyimide composite an ideal structural material for solar sails, solar arrays and thin-film photovoltaics, etc. Graphical abstract: Image 1 Highlights: Ionic liquid/polyimide composites exhibit outstanding foldability, flexibility, processability and optical transparency. This 23-μm-thick polyimide composite film exhibits a high optical transmittance of 90.4% even at 450 nm wavelength and an incredibly low cutoff wavelength of 273 nm. This composite material has a super folding capability with a minimum bending radius of 1 μm, which is to our knowledge the lowest record for polymide materials.