Wearable and Robust Polyimide Hydrogel Fiber Textiles for Strain Sensors

Abstract

Conductive ionic hydrogel fibers and textiles with excellent mechanical properties and chemical stability are requested for flexible and wearable electronic devices, strain sensors, and even artificial skin. However, most of the reported hydrogel fibers are not suitable in complex environments, especially in alkaline solutions and organic solvents due to their poor chemical stability. Herein, we report ionic polyimide hydrogel fibers derived from an organosoluble polyimide salt that can be continuously and rapidly prepared via a facile wet spinning method. Thanks to their ion-rich property and robust skeletal structure, the obtained ionic polyimide hydrogel fibers showed an excellent conductivity of ∼21 mS/cm and outstanding mechanical properties with a tensile strength of 2.5 MPa and breaking elongation of 215%. Furthermore, the as-prepared fibers could be easily woven to form integral textiles, endowing them with good wearable properties. Accordingly, facile strain sensors assembled by polyimide hydrogel fibers show a linear response with high sensitivity and good cycling stability, which have great potential for applications in wearable and flexible strain sensors under diverse complex environments.

Preparation and characterization of porous polyimide fibers with electromagnetic wave absorption properties

“…The EDS spectrum showed the presence and distribution of C, N, Fe, and O in the fiber, and the results make sure the structural uniformity and integrality of the composite fibers. [41] As everyone knows, the ordered orientation of the macromolecular chains has important implication to achieve the outstanding application property of polymeric fiber. The 2D-WAXD experiment was carried out to amply research the microstructure evolution process under different temperature of coagulation bath and the consequence is demonstrated in Figure 3A-C.…”

Flexible and wearable strain sensors based on conductive hydrogels

“…In addition, the saline solution is also used as a reinforcer to provide coordination ions to enhance the interaction of the polymer backbone. Li and coworkers 50 reported a hydrogel based on polyimide hydrogel fiber textiles. The CaCl 2 solution served as a coagulation bath for providing calcium ions to interact with carboxyl groups on the polymer backbone.…”

“…(A) ΔR/R0‐ strain curve of the hydrogel fiber at 0%–100% strain. (B) Relative resistance changes of the hydrogel fiber strain sensor bending from 0 to 180° and holding at 180° for approximately 10 s. Reproduced with permission 50 . Copyright 2021, American chemistry society.…”

“…(B) Relative resistance changes of the hydrogel fiber strain sensor bending from 0 to 180 and holding at 180 for approximately 10 s. Reproduced with permission. 50 Copyright 2021, American chemistry society. (C) The hydrogel exhibits excellent strength and toughness, confirmed by weight loading.…”

Perfluorocyclobutyl-containing transparent polyimides with low dielectric constant and low dielectric loss

“…11 Among the diverse highperformance polymer materials, polyimides are known as a "problem solver" because of their excellent integrative properties including excellent flexibility, thermal stability, solvent resistance and mechanical strength. [12][13][14][15] Nonetheless, the polar imide group endows the polyimide with a relatively high dielectric constant (around 3.5), which does not meet the requirements of the microelectronics industry. 16 From the perspective of molecular structure design, there are two main strategies to lower the dielectric constant in polyimides: one is introducing large pendant groups to decrease the packing density of the polyimide chains; 5,[17][18][19] the other is increasing the amount of fluorine atoms on the polyimide backbone to reduce the polarization ability.…”