Semi‐Interpenetrating Polymer Network Biomimetic Structure Enables Superelastic and Thermostable Nanofibrous Aerogels for Cascade Filtration of PM_2.5

Abstract

Particulate matter (PM) has taken heavy tolls on the global economy and public health, calling for air filters that can remove PM from high‐temperature emission sources. However, creating desirable filter media capable of capturing polydisperse fine particles (PFPs) effectively and enduringly, while also withstanding high speed airstream, is extremely challenging. Here, a biomimetic and bottom‐up strategy to prepare superelastic, strong, and thermostable nanofibrous aerogels (NFAs) as cascade filters by assembling semi‐interpenetrating polymer network (semi‐IPN)‐based nanofibers into a gradient architecture is reported. Inspired by the robust loofah sponges originating from stiff cellulose networks, the mechanical property of NFAs is enhanced via tailoring the chain flexibility of heat‐resistant semi‐IPNs. Further constructing a gradient cellular architecture endows NFAs with a versatile cascade filtration behavior for capturing polydisperse fine particles. The resultant semi‐IPN‐based gradient NFAs exhibit temperature‐invariant superelasticity, a high compressive stress (7.9 kPa) and modulus (12 kPa), high filtration efficiency (>99.97%, PM0.3), low pressure drop (≈50% that of membranes), and ultrahigh dust‐holding capacity (114 g m−2). The fabrication of this attractive material paves the way for designing next‐generation air filters for industrial dust removal.

Superhydrophobic polyvinylidene fluoride/polyimide nanofiber composite aerogels for thermal insulation under extremely humid and hot environment

“…Hence, constructing nanofibers into 3D nanofiber aerogels may be an eminent strategy for achieving promising properties in a wide range of applications. At present, many polymers, such as polyacrylonitrile (PAN) [25], poly(vinyl alcohol) (PVA) [32] and polyamideimide (PAI) [33], have been electrospun into nanofibers for the manufacture of 3D nanofiber aerogels. For instance, polyimide (PI) nanofibers have recently been employed as building blocks and fabricated into nanofiber aerogels due to their excellent mechanical strength, flexibility, thermostability and solvent resistance [34,35].…”

Recent advances in novel aerogels through the hybrid aggregation of inorganic nanomaterials and polymeric fibers for thermal insulation

“…Actually, the aerogels sometimes are sensitive to the moisture environmental conditions (e.g., handling and storage), and likely to become more brittle with ageing and exhibit stress relaxation behaviors. To avoid the collapse of aerogels during cyclic compression, the semi‐interpenetrating frameworks have been developed to improve their elasticity by forming bonding points between each nanofiber (seen in Figure 11A) [ 135 ] Compared to traditional aerogels, nanocellulose with low shrinkage and higher crystallinity often been used as the supporting material and integrated with the other components, resulting in a diverse novel material inherent mechanical property. [ 126 ] The nanomaterials (e.g., nanofibers) can be further functionalized to increase their interfacial interactions with the matrix, resulting a three‐dimensional interconnected hierarchical microstructure and enhanced mechanical strength of the aerogels.…”

Interlocked Dual‐Network and Superelastic Electrospun Fibrous Sponges for Efficient Low‐Frequency Noise Absorption

“…Alternatively, newly developed electrospun fibers with desirable merits such as small fiber diameter and high channel curvature, which can provide more acoustic contact area and friction probability, have shown huge prospects in the field of low‐frequency noise reduction. [ 13–16 ] Nevertheless, this kind of material is generally assembled into close‐packed fiber membranes (with thickness <100 μm) caused by its anisotropic lamellar deposition character, [ 17–19 ] and thereby lacks enough dissipation paths for low‐frequency noise.…”