Due to the large specific surface area and continuous pores in structures, metal–organic frameworks (MOFs) show great advantages in the adsorption of volatile organic compounds (VOCs). Photonic crystal (PC) sensors derived from MOFs are promising for the visual detection of VOC gases. However, they still have problems of low sensitivity and poor color saturation and tunability. Here, inspired by vapor-sensitive scales of Tmesisternus isabellae beetle and scattering light absorption of polydopamine, a porous one-dimensional PC sensor is constructed by combining ZIF-8 with TiO2@PDA nanoparticles. The PC sensor shows significant color changes under different concentrations of benzene vapor and reaches a detection limit of 0.8 g/m3. It has a response time of less than 1 s and maintains stable optical performance after 100 times of reuse. Moreover, ZIF-67 and ZIF-7 are both incorporated into the PCs for comparison; it reveals that ZIF-8 shows superior benzene detecting property. Additionally, the synergistic adsorption of VOCs in inner and outer holes of the ZIF-8 layer is demonstrated by real-time mass monitoring with quartz crystal microbalance with dissipation. This study provides a valuable reference for the fabrication of high-quality MOF-based PC sensors and sensing mechanism study between microscopic molecular adsorption and macroscopic performance.
Encouraged by the strategy of increasing efficiency and reducing pesticide overuse, the development of polymer/surfactant as additives to enhance pesticide droplet deposition on hydrophobic leave is a promising project. Herein, Alginate-based supra-amphiphiles (SAs), host–guest self-assembled by host amphiphilic cyclodextrin-functionalized alginate derivative (Alg-CD) and guest azobenzene-based surfactant (Azo-DEMA), performed comprehensive characteristics, which integrated the viscosity effect and the ability to reduce surface tension. SAs enabled oil-in-water pesticide droplets to inhibit splashing and light-regulate wetting, thereby enhancing droplets deposition. By analyzing the impact dynamics of loaded-pesticide o/w droplets on hydrophobic surface, the addition of SAs rapidly afforded the pinning ability of droplets with the target surface, and in turn, resulted in inhibiting splashing. Afterward being exposed to UV light, the resulting SAs o/w droplets undergone disassembly so as to release small-molecular surfactant and reduce the surface tension of droplets for improving droplets’ wettability. Importantly, quartz crystal microbalance with dissipation monitoring (QCM-D) was skillfully used for revealing the interaction mechanism between droplets and the waxy layer of hydrophobic surface, finding that SAs could form compact conformation on the waxy surface, while disassembled SAs undergoing UV irradiation exhibited the large adsorption amount and stronger interaction with waxy layer. Consequently, the herbicidal activity experiments exhibit sensitive pesticide control effects assessed under UV even natural sunlight. Light-regulating host–guest interfacial interaction of polysaccharide-based supra-amphiphiles may provide a novel, eco-friendly and feasible manner for comprehensive pesticide applications.
危险品化学品经营许可证（带存储）