Trap-Induced Dense Monocharged Perfluorinated Electret Nanofibers for Recyclable Multifunctional Healthcare Mask.

Recently, wearable and breathable healthcare devices for air filtering and real-time vital signs monitoring have become urgently needed since virus and particulate matter (PM) cause serious health issues. Herein, we present a trap-induced dense monocharged hybrid perfluorinated electret nanofibrous membrane (HPFM) for highly efficient ultrafine PM0.3 removal with an efficiency of 99.712% under low pressure drop (38.1 Pa) and high quality factor of 0.154 Pa-1. Furthermore, a recyclable multifunctional healthcare mask is constructed by integrating the HPFM-based nanogenerator, which realizes efficient PM0.3 filtering and wireless real-time human respiration monitoring simultaneously. More importantly, the performance of this mask is still relatively stable even at 100%RH humidity and 92 °C temperature conditions for 48 h, which infers that it can be reused after disinfection. The strategy of fabricating HPFM provides an approach to obtain charge-rich stable electret materials, and the design of multifunctional masks demonstrates their potential application for future personal protection and health monitoring devices.

Quaternary Ammonium-Bearing Perfluorinated Polymers for Anion Exchange Membrane Applications.

Perfluorinated polymers are widely used in polymer electrolyte membranes because of their excellent ion conductivity, which are attributed to the well-defined morphologies resulting from their extremely hydrophobic main-chains and flexible hydrophilic side-chains. Perfluorinated polymers containing quaternary ammonium groups were prepared from Nafion- and Aquivion-based sulfonyl fluoride precursors by the Menshutkin reaction to give anion exchange membranes. Perfluorinated polymers tend to exhibit poor solubility in organic solvents; however, clear polymer dispersions and transparent membranes were successfully prepared using N-methyl-2-pyrrolidone at high temperatures and pressures. Both perfluorinated polymer-based membranes exhibited distinct hydrophilic-hydrophobic phase-separated morphologies, resulting in high ion conductivity despite their low ion exchange capacities and limited water uptake properties. Moreover, it was found that the capacitive deionization performances and stabilities of the perfluorinated polymer membranes were superior to those of the commercial Fumatech membrane.

Investigating the Strain, Temperature and Humidity Sensitivity of a Multimode Graded-Index Perfluorinated Polymer Optical Fiber with Bragg Grating.

In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by using a krypton fluoride (KrF) excimer laser and the phase mask method. The evolution of the reflection spectrum of the FBG detected with a multimode interrogation technique revealed a single reflection peak with a full width at half maximum (FHWM) bandwidth of about 9 nm. Furthermore, the spectral envelope of the single FBG reflection peak can be optimized depending on the KrF excimer laser irradiation time. A linear shift of the Bragg wavelength due to applied strain, temperature and humidity was measured. Furthermore, depending on irradiation time of the KrF excimer laser, both the failure strain and strain sensitivity of the multimode fiber with FBG can be controlled. The inherent low light attenuation in the near infrared wavelength range (telecommunication window) of the multimode CYTOP fiber and the single FBG reflection peak when applying the multimode interrogation set-up will allow for new applications in the area of telecommunication and optical sensing.

Radiation-Induced Attenuation of Perfluorinated Polymer Optical Fibers for Radiation Monitoring.

Due to some of their unique properties, optical fiber dosimeters are attractive and extensively researched devices in several radiation-related areas. This work evaluates the performance and potential of commercial perfluorinated polymer optical fibers (PF-POFs) for radiation monitoring applications. Gamma radiation-induced attenuation (RIA) of two commercial PF-POFs is evaluated in the VIS spectral region. Influence of a dose rate and temperature on RIA measurement is investigated, along with defect stability and measurement repeatability. Co-extruded PF-POFs are identified as more suitable for radiation monitoring applications due to lower dose-rate dependence. With co-extruded PF-POF, RIA measurement holds potential for highly-sensitive radiation monitoring with good reproducibility. The results show that operation in the blue part of the spectrum provides most favorable performance in terms of the largest nominal radiation sensitivity, lower temperature, and dose-rate dependence as well as higher defect stability. We demonstrate for the first time to our knowledge, that PF-POFs can be used for distributed detection of radiation with doses down to tens of Grays. The off-the-shelf, user-friendly PF-POF could be of interest as a cheap, disposable sensor for various applications, especially of a more qualitative nature.