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The spontaneous generation of hydrogen peroxide (H 2 O 2 ) within atmospheric microdroplets, such as raindrops and aerosols, plays a crucial role in various environmental processes including pollutant degradation and oxidative stress. However, quantifying hydroxyl radicals (•OH), essential for H 2 O 2 formation, remains challenging due to their short lifespan and low concentration. This study addresses this gap by presenting a highly sensitive and selective surface-enhanced Raman scattering (SERS) nanosensor specifically designed for quantifying •OH within water microdroplets. Utilizing a phthalhydrazide (Phth) probe, the SERS technique enables rapid, interference-free detection of •OH at nanomolar concentrations. It achieves a linear detection range from 2 nM to 2 μM and a limit of detection as low as 0.34 nM. Importantly, the SERS sensor demonstrates robustness and accuracy within water microdroplets, paving the way for comprehensive mechanistic studies of H 2 O 2 generation in the atmosphere. This innovative approach not only offers a powerful tool for environmental research but also holds potential for advancing our understanding of atmospheric H 2 O 2 formation and its impact on air quality and pollutant degradation.

Fabrication of a gel polymer electrolyte containing succinonitrile (GPE-SN) with high mechanical strength is quite challenging because the SN electrolyte always suppresses the formation of polymer networks during in situ polymerization. In this work, a mechanically robust GPE-SN was successfully prepared by using a solution immersion method. During fabrication, the paste-like SN electrolyte was transformed into a liquid SN electrolyte with low viscosity by heating at 50 °C and then infiltrated into the UV-cured highly cross-linked polyurethane acrylate (PUA) skeleton. The resulted GPE-SN film exhibits superior tensile strength (6.5 MPa) compared to the one (0.5 MPa) prepared by in situ polymerization (GPE-SN-IN). The high mechanical strength of the GPE-SN-IM film enables the LiCoO 2 /Li 4 Ti 5 O 12 film battery to withstand 100-cycle folding without electrolyte damage and capacity loss. Besides, the GPE-SN presents a high ionic conductivity (1.63 × 10 -3 S·cm -1 at 25 °C), which is comparable to GPE with a commercial liquid electrolyte (GPE-LE). Because of good thermal stability of the GPE-SN, the LiCoO 2 /Li cell with this electrolyte shows better charge-discharge cycling stability than that with GPE-LE at high temperature (55 °C). Thus, the GPE-SN prepared by our method could be a promising polymer electrolyte offering better safety and reliability for lithium-ion batteries.

Constructing a dense cross-linking layer on a polymer film surface is a good way to improve the water resistance of poly(lactic acid) (PLA). However, conventional plasma treatments have failed to achieve the aim as a result of the unavoidable surface damage arising from the charged species caused by the uncontrolled high energy coming from colliding ions and electrons. In this work, we report a modified plasma method called hyperthermal hydrogen-induced cross-linking (HHIC) technology to construct a dense cross-linking layer on PLA film surfaces. This method produces energy-controlled neutral hyperthermal hydrogen, which selectively cleaves C-H bonds by molecule collision from the PLA film without breaking other bonds (e.g., C-C bonds in the polymer backbone), and results in subsequent cross-linking of the carbon radicals generated from the organic molecules. The formation of a dense cross-linking layer can serve as a barrier layer to significantly improve both the hydrophobicity and water vapor barrier property of the PLA film. Because of the advantage of selective cleavage of C-H bonds by HHIC treatment, the original physical properties (e.g., mechanical strength and light transmittance) of the PLA films are well-preserved.

There is a growing shift from liquid electrolytes toward solid polymer electrolytes, in energy storage devices, due to the many advantages of the latter such as enhanced safety, flexibility, and manufacturability. The main issue with polymer electrolytes is their lower ionic conductivity compared to that of liquid electrolytes. Nanoscale fillers such as silica and alumina nanoparticles are known to enhance the ionic conductivity of polymer electrolytes. Although carbon nanotubes have been used as fillers for polymers in various applications, they have not yet been used in polymer electrolytes as they are conductive and can pose the risk of electrical shorting. In this study, we show that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers. We show that such hybrid nanofillers increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude. Furthermore, significant improvement in mechanical properties were observed where only 5 wt % addition of the filler led to 160% increase in the tensile strength of the polymer. This new approach of embedding conducting-insulating hybrid nanofillers could lead to the development of a new generation of polymer nanocomposite electrolytes with high ion conductivity and improved mechanical properties., (© 2012 American Chemical Society)

In this work, a great synergistic effect of 2D clay platelets and 1D carbon nanotubes (CNTs) on reinforcing chitosan matrix has been observed for the first time. With incorporation of 3 wt % clay and 0.4 wt % CNTs, the tensile strength and Young's modulus of the nanocomposites are significantly improved by about 171 and 124%, respectively, compared with neat chitosan. This could be understood as due to the formation of much jammed fillers network with 1D CNTs and 2D clay platelets combined together, as indicated by rheological measurement. Our work demonstrates a good example for the preparation of high performance polymer nanocomposites by using nanofillers of different dimension together.

Covalent functionalization of shortened multiwalled carbon nanotubes (MWNTs) with a natural low molecular weight chitosan (LMCS) was accomplished by a nucleophilic substitution reaction. Amino and primary hydroxyl groups of the LMCS contributed mainly to the formation of MWNT-LMCS conjugates. The LMCS content in the MWNT-LMCS is approximately 58 wt %, and approximately four molecular chains of the LMCS are attached to 1000 carbon atoms of the nanotube sidewalls. Most interestingly, the amorphous packing structure of the LMCS changed dramatically when it attached to the MWNTs. The MWNTs might induce the crystalline character of the LMCS. As a novel derivative of MWNTs, the MWNT-LMCS is soluble in dimethylformamide, dimethyl acetamide, dimethylsulfoxide, and acetic acid aqueous solution. The confirmation of the chitosan-based covalent functionalization route might lead to further studies aiming for potential applications in catalysis and environmental protection.