Haohui Zheng,Gaofeng Chen,Lihui Gan,Jian Liu,Lu Lin
Ultra-light elastic carbon aerogels with high compressibility have broad application prospects in wearable devices. Especially, they are ideal materials for fabricating flexible piezoresistive sensors. In this paper, an ultra-light carbon aerogel was successfully fabricated using freeze-drying and carbonization of the solution containing chitosan (CS), polyimide (PI), and FeCl3·6H2O. Owing to the interplay interaction between CS and PI and the adjustment of the FeCl3 concentration, this carbon aerogel with compact, continuous, ordered, layered structure shows a wide range of excellent sensing properties (10.28 kPa–1 and 0–6 kPa), remarkable long-term stability (1000 cycles), and outstanding mechanical properties (withstand up to 95% compression strain and 1000 cycles compression under 50% strain without deformation). In addition, the carbon aerogel can be bent to detect different angular changes. These advantages mentioned above allow carbon aerogel to be wildly used to detect human movement and biological signals.
Developing efficient and reliable adsorbents with simplified synthesis and mixed-mode performance is crucial for the accurate quantitative analysis of diverse coexisting environmental pollutants. A magnetic carboxylated hypercrosslinked organic polymer (Fe 3 O 4 /HCP-COOH) with reverse phase/cation exchange mixed-mode performance was synthesized through a two-stage process: (1) Fabrication of HCP-COOH via FeCl 3 -catalyzed Friedel-Crafts alkylation using 1,4-phenylenediacetic acid and 1,4-bis(chloromethyl)benzene; (2) In situ growth of Fe 3 O 4 nanoparticles on HCP-COOH through coprecipitation, utilizing FeCl₃ dually as polymerization catalyst and iron precursor to enhance process efficiency and waste minimization. The nanocomposite functioned as a mixed-mode sorbent for magnetic solid-phase extraction (MSPE), integrating dual retention mechanisms to selectively extract hydrophobic polycyclic aromatic hydrocarbons (PAHs) and cationic quaternary ammonium pesticides (QUATs), with subsequent analysis by GC-MS for PAHs and HPLC-MS/MS for QUATs respectively. Following optimization of adsorption pH, eluent composition, and contact time, the method exhibited high sensitivity with limits of detection (LODs) of 0.80-7.93 ng L⁻¹ for 15 PAHs and 0.02-16.31 ng L⁻¹ for 4 QUATs. Validation showed satisfactory recoveries of 89.5-98.3% (RSDs ≤11.2%) in snowmelt and 90.4-101.8% (RSDs ≤11.6%) in lake water (n=3), confirming practicality for simultaneous monitoring of hydrophobic and cationic contaminants in complex environmental water, offering significant advantages in multi-residue analysis for environmental monitoring applications.
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