Solvent Vapor Strengthened Polyimide Nanofiber-Based Aerogels with High Resilience and Controllable Porous Structure

Abstract

Owing to the hierarchically three-dimensional (3D) network, ultralow density, and high porosity, nanofiber-based aerogels (NFAs) have drawn great attention recently. However, precise control of the porous structure and mechanical properties of NFAs, which have been proved to be extremely essential to the applications, still remains a major challenge. Herein, electrospun polyimide (PI) nanofibers were utilized as building blocks to construct NFAs through the solid-templating technique. The porous structure of PI nanofiber-based aerogels (PI-NFAs) could be adjusted by changing the processing parameters. By further welding the adjacent nanofibers at the contact sites with solvent vapor, high-resilience PI-NFAs were successfully prepared with comparable or higher recoverable, under compression, folding and torsion relative to other NFAs. The welded PI-NFAs showed ultralow density (minimum of 0.96 mg/cm3), high porosity (maximum of 99.93%), and tunable hierarchical structure. Therefore, this study brought a new perspective on the simple preparation of high-resilience nanofiber-based aerogels with tunable porous structures.

Superelastic Polyimide Nanofiber-Based Aerogels Modified with Silicone Nanofilaments for Ultrafast Oil/Water Separation

“…As shown in Figure , PI nanofibers were prepared following the methods in our previous publication . Uniform nanofibers with an average diameter of 261.48 ± 65.15 nm (Figure S1) were obtained.…”

“…In this work, electrospun polyimide (PI) nanofibers were chosen as the building blocks because of chemical resistance, excellent thermal-oxidative stability, and good mechanical strength. , Herein, we proposed to construct novel composite PI nanofiber-based aerogels (PI-NFAs) with 3D tortuosity and a hierarchical structure by reconstructing the intrinsically lamellar-deposited electrospun nanofibers. PI-NFAs were prepared via a 3D reconstruction strategy reported previously, which were further bonded together at the cross-points. Afterward, ultrafine silicone nanofilaments (SiNFs) were coated on the surface, converting PI-NFAs into a superhydrophobic material.…”

Super-elasticity at 4 K of covalently crosslinked polyimide aerogels with negative Poisson’s ratio

“…Furthermore, the decomposition of PAAS in water cannot be completely avoided as a result of imperfect salinization of poly (amic acid) (PAA), leading to weak resilience of elastic PI aerogels because of low molecular weight. The recently emerged electro-spun nanofibrous PI aerogels provide an effective pathway to avoid the large shrinkage and decomposition of PAAS in water 35 – 37 , but the incorporation of the electro-spun process complicates the whole fabrication process and increases the costs.…”

Recent Progress in Conducting Polymer Composite/Nanofiber-Based Strain and Pressure Sensors

“…Three-dimensional nanofibrous porous aerogels welding is done with various organic solvents and with optimized time and temperatures. In particular, the champion mechanically resilient welded strain sensor was achieved with a 60 • C DMF solvent vapor treatment [180]. Improvements in durability are challenging and have posed consistent challenges in the past, which are addressed via morphological engineering, microstructure patterning, and composite reinforcements.…”