Multiscale Structural Nanocellulosic Triboelectric Aerogels Induced by Hofmeister Effect

Abstract

The advent of self‐powered wearable electronics will revolutionize the fields of smart healthcare and sports monitoring. This technological advancement necessitates more stringent design requirements for triboelectric materials. The triboelectric aerogels must enhance their mechanical properties to address the issue of structural collapse in real‐world applications. This study fabricates stiff nanocellulosic triboelectric aerogels with multiscale structures induced by the Hofmeister effect. The aggregation and crystallization of polymer molecular chains are enhanced by the Hofmeister effect, while ice crystal growth imparts a porous structure to the aerogel at the micron scale. Therefore, the triboelectric aerogel exhibits exceptional stiffness, boasting a Young's modulus of up to 142.9 MPa and a specific modulus of up to 340.6 kN m kg–1, while remaining undeformed even after supporting 6600 times its weight. Even after withstanding an impact of 343 kPa, highly robust wearable self‐powered sensors fabricated with triboelectric aerogels remain operational. Additionally, the self‐powered sensor is capable of accurately detecting human movements, particularly in abnormal fall postures detection. This study provides considerable research and practical value for promoting material design and broadening application scenarios for self‐powered wearable electronics.

High Strength and Toughness Polymeric Triboelectric Materials Enabled by Dense Crystal-Domain Cross-Linking

“…As shown in Figure S5, the melting peak signal strengthens with increasing sodium citrate concentration (0.5−2.0 M), indicating enhanced crystallinity. 37,38 Similarly, the XRD pattern in Figure 2g reveals an intensified characteristic peak at 2θ = 19.3°, further corroborating this trend. 39 Moreover, the peak intensity directly correlates with salt concentration, reaching a maximum crystallinity of 75.46% at 2 M (Figure 2h).…”

“… This indicates that the increase in crystallinity is mainly attributed to the growth in the number of crystalline domains rather than the size of the individual domains. Figure d illustrates the SAXS patterns, according to the Bragg equation, the distance between adjacent crystalline domains is reduced from 10.1 to 8.4 nm based on the scattering vector at the peak position. , The 2D diffraction pattern from WAXS also confirmed the increase in the aggregation state of the polymer chains, that is, the distance between adjacent crystalline domains decreased . Furthermore, the characteristic peaks of the hydroxyl groups of the polymeric triboelectric material shifted to a higher wavenumber (Figure e), indicating that the salting-out effect affects polymer hydrogen bonding, enhancing the intermolecular interactions between polymer chains .…”

“…Moreover, the peak intensity directly correlates with salt concentration, reaching a maximum crystallinity of 75.46% at 2 M (Figure h). The subsequent decrease at 2.5 M is attributed to excessive anions disrupting polymer aggregation, thereby hindering stress dissipation and compromising mechanical properties. , As shown in Figure i, the charge density exhibits a positive correlation with salt concentration from 0.5 to 2.0 M, and it is higher than the charge density of the original polymer film (Figure S6). In addition, the charge density decreases sharply at 2.5 M, mirroring the crystallinity trend.…”

“…24,42 The 2D diffraction pattern from WAXS also confirmed the increase in the aggregation state of the polymer chains, that is, the distance between adjacent crystalline domains decreased. 38 Furthermore, the characteristic peaks of the hydroxyl groups of the polymeric triboelectric material shifted to a higher wavenumber (Figure 4e), indicating that the salting-out effect affects polymer hydrogen bonding, enhancing the intermolecular interactions between polymer chains. 44 Therefore, the ion-specific effects can be utilized to regulate the crystalline domains, influencing the stretchability and stress resistance of the polymer network, ultimately achieving control of mechanical properties.…”

Lightweight and Strong Cellulosic Triboelectric Materials Enabled by Cell Wall Nanoengineering

“…Porous materials show great potential as triboelectric materials because of their excellent mechanical and lightweight properties . They also have high porosity and low density, which make them suitable for wearable electric sensing. − However, porous materials tend to collapse under deformation, which compromises their structural stability and sensing signal accuracy. To overcome this challenge, various methods have been used to fabricate strong porous materials, such as template synthesis, , emulsion template, and additive manufacturing .…”