Phase separation of a PVDF–HFP film on an ice substrate to achieve self-polarisation alignment. (February 2023)

• Record Type: Journal Article
• Authors: Liu, Yulun; Tong, Wangshu; Wang, Lingchao; Zhang, Panpan; Zhang, Jiahe; Wang, Xuemei; Zhang, Shuai; Liu, Ya; Liu, Songling; Wang, Shengqian; Chai, Mengnan; Zhang, Yihe
• Is Part Of: Nano energy. Volume 106(2023)
• Publication Date: 2023-02
• Subjects: Self-polarisation -- Aqueous phase separation -- Poly(vinylidene fluoride-co-hexafluoropropylene) film -- Ice substrate; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2022.108082
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Flexible self-polarised poly(vinylidene fluoride) (PVDF) piezoelectric films that have a high electroactive phase content and can be easily prepared are applied in force–electricity conversion, particularly as self-power supplies for small devices and the detection of body signals. Filler addition, phase separation and polarisation by a substrate are the most used methods to fabricate self-polarised PVDF films. However, the alignment of films is hard to realise using these self-polarising techniques, thus making it difficult to increase piezoelectric generation. In this study, phase separation on an ice substrate was used to prepare a self-polarised poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF–HFP) film. Strong polarisation via hydrogen bonding between PVDF–HFP and a flat ice substrate contributes toward a high β-phase content of 86.5% and good film alignment. Moreover, the low preparation temperature provided by ice has considerable impact on self-polarisation, with excellent alignment observed because of the reduced disturbance by solvent flow and the Brownian motion of the PVDF–HFP solution at low temperature having less impact on self-polarisation via hydrogen bonding. The phase separation on ice of the PVDF–HFP film was confirmed to be an efficient self-polarisation method to considerably improve its β-phase content, alignment and piezoelectric generation performance. Graphical Abstract: ga1 Highlights: PVDF-HFP film on ice exhibited the highest β-phase content of 86.5% and the best generation ability as TENG and PENG. Provides new insight into phase separation for alignment by self-polarisation. The mechanical support effects and hydrogen bonding of ice on the alignment were proved by PFM. The effects of different modes of contact between H2 O and PVDF–HFP on the self-polarisation of PVDF–HFP were investigated.