'Donor-acceptor', 'interpenetrating polymer network' and 'electrostatic self-assembly' work in tandem to achieve extraordinary specific shielding effectiveness

The exploration of 'electrostatic self-assembly' on solid surfaces has garnered significant interest across various fields. With the sophistication of gadgets, managing electromagnetic interference (EMI) from stray signals, especially in stealth applications, necessitates materials that can absorb microwaves. A promising approach involves integrating lightweight self-healing polymeric materials. This study employs electrostatic self-assembly to design a carbon nanotube structure on an interpenetrating polymer network (IPN) made of PVDF and bismaleimide (BMI)-grafted dopamine hydrochloride, enhancing mechanical integrity through well-formed IPNs. Graphene oxide (GO) is introduced before IPN formation to facilitate an 'acceptor-donor' interaction via the Diels-Alder adduct between BMI and GO, which binds with multi-walled carbon nanotubes (MWCNTs). MWCNTs, modified with PQ7 or PDDA for a positive charge, self-assemble onto the IPN-GO construct, creating a lightweight and chemically stable structure capable of absorbing electromagnetic radiation. The 21 μm thick construct exhibits enhanced microwave absorption within the X-band (8.2-12.4 GHz), with a specific shielding effectiveness of 8637 dB cm2 g-1 and a green index (gs ≈ 1.41). The construct is coated with self-healable polyetherimide (PEI) containing exchangeable disulfide bonds to address maintenance challenges, providing heat-triggered self-healing properties. These innovative structures offer solutions for 5G and IoT applications where lightweight, durable, and multifunctional properties are essential for effectively shielding electronic devices from stray signals.

Polyvinylidene fluoride/graphene oxide/polyimide composite high-efficiency PM2.5 filtration nanofiber membranes

Particulate air pollution is a global environmental problem, with PM2.5 being the primary pollutant. One of the most effective ways to remove particles from the air is through filtration. Therefore, high-performance air filters are urgently needed to combat the harm caused by PM2.5. This study uses an electrospinning technique to prepare high-efficiency polyvinylidene fluoride/graphene oxide/polyimide nanofiber membranes. These composite nanofiber membranes demonstrate high filtration efficiency (99.6%), low pressure drop (123 Pa), remarkable thermal stability (450 °C), and excellent mechanical strength (7 MPa). Considering the advantages, these highly efficient nanofiber membranes can find advanced applications in industrial and civil infrastructures.

Development of new magnetic nanocomposite designed by reduced graphene oxide aerogel and HKUST-1, and its catalytic application in the synthesis of polyhydroquinoline and 1,8-dioxo-decahydroacridine derivatives

In this study, new magnetic reduced graphene oxide aerogel/HKUST-1 nanocomposite was designed and synthesized given the transformation of graphene oxide sheets to three-dimensional reduced graphene oxide aerogel, the in-situ magnetization of aerogel substrate, and the in-situ formation of HKUST-1 particles. Apart from characterizing the chemistry and structure of the designed magnetic nanocomposite (FT-IR, EDX, ICP, FE-SEM, DLS, XRD, VSM, and TG analyses), its catalytic performance was evaluated in the one-pot synthesis of biologically active 1,8-dioxo-decahydroacridine and polyhydroquinoline derivatives. The combination of magnetized reduced graphene oxide aerogel and HKUST-1 in the form of a new heterogeneous magnetic nanocatalyst was accompanied by a high synergetic catalytic effect in the symmetric and unsymmetrical Hantzsch condensation reactions. Compared to previous research studies, the pharmaceutical 1,8-dioxo-decahydroacridine and polyhydroquinoline derivatives can be synthesized using a partial amount of this nanocatalyst with a high percentage of yields in a short reaction time.

Three dimensional high-performance micro-supercapacitors with switchable high power density and high energy density

In the field of microscale energy storage, the fabrication of micro-supercapacitors (MSCs) with high power density and high energy density has always been a focus of research. In this work, laser-induced porous graphene and chemically deposited manganese dioxide nanoparticles are used as electrode materials, and a switchable MSC with two energy storage principles is obtained by designing symmetric interdigitated and square electrode structures. The aim is to overcome the preparation challenge of supercapacitors with high energy density and high power density by switching between two modes. In this MSC, the energy density of the high energy density mode (5.89 μW h cm-2) is 3.36 times that of the high power density mode (1.75 μW h cm-2), while the power density of the high power density mode (43.06 μW cm-2) is 1.44 times that of the high energy density mode (29.96 μW cm-2). In addition, under the drive of five serially connected MSCs, 27 LED lights can be continuously lit for 5 minutes. Therefore, this work provides a facile and novel method for the development of MSCs with high power density and high energy density, suggesting a great practical application value in the development of MSCs.

Highly conducting corn starch doped ionic liquid solid polymer electrolyte for energy storage devices-RAFM 2022

In this study, a new biopolymer electrolyte (BPE) is successfully developed using corn starch complexed with ammonium iodide (NH4I) as host, and low viscosity ionic liquid 1-Ethyl, 3-Methyl Imidazolium Thiocyanate (EMImSCN), as a plasticizer. This ionic liquid doped BPE shows high ionic conductivity of the order 10−4 S/cm and electrochemical stability window more than 3 V, which is suitable for electrochemical application. The ionic transference number (tion) of 0.98 confirms the system to be predominantly ionic in nature. Fourier transform infrared spectroscopy (FTIR) shows complex nature, while polarized optical microscopy (POM) gives us an idea about the semi-crystalline nature of BPE. Maximum conducting ionic liquid doped BPE sandwiched electric double layer capacitor (EDLC) and dye sensitize solar cell (DSSC) shows efficient performance.

Polyethylene-oxide: NaI polymer electrolyte: Electrical, structural and photoelectrochemical studies- RAFM

Conducting sodium iodide (NaI) doped polyethylene oxide (PEO) freestanding electrolyte films are prepared by solution cast technique. Electrical, Structural, and device performances are given in detail. Maximum conducting polymer electrolyte has been used to develop electric double-layer capacitors (EDLCs) as well as the dye-sensitized solar cell (DSSC) which shows that ion-conducting polymer electrolyte is a novel candidate for energy devices.

Polymer grafted magnetic graphene oxide as a potential nanocarrier for pH-responsive delivery of sparingly soluble quercetin against breast cancer cells

In this work, polymer grafted magnetic graphene oxide (GO-PVP-Fe3O4) was successfully synthesized for efficient delivery of anticancer drug. Firstly, GO was functionalized with the hydrophilic and biocompatible polymer polyvinylpyrrolidone (PVP) and then grafted with magnetic nanoparticles (Fe3O4) through an easy and effective chemical co-precipitation method. Quercetin (QSR) as an anticancer drug was loaded onto the surface of GO-PVP-Fe3O4 via non-covalent interactions. The drug loading capacity was as high as 1.69 mg mg-1 and the synthesized magnetic nanocarrier shows pH-responsive controlled release of QSR. The cellular cytotoxicity of the synthesized nanocarrier with and without drugs was investigated in human breast cancer MDA MB 231 cells and their effects compared on non-tumorigenic epithelial HEK 293T cells. These results reveal that the drug loaded GO-PVP-Fe3O4 nanohybrid was found to be more toxic than the free drug towards MDA MB 231 cells and exhibits biocompatibility towards HEK 293T cells. Overall, a smart drug delivery system including polymer grafted magnetic graphene oxide as a pH-responsive potential nanocarrier could be beneficial for targeted drug delivery, controlled by an external magnetic field as an advancement in chemotherapy against cancer.

Mass production of metal-doped graphene from the agriculture waste of Quercus ilex leaves for supercapacitors: inclusive DFT study

This work reports a facile, eco-friendly, and cost-effective mass-scale synthesis of metal-doped graphene sheets (MDGs) using agriculture waste of Quercus ilex leaves for supercapacitor applications. A single step-degradation catalyst-based pyrolysis route was used for the manufacture of MDGs. Obtained MDGs were further evaluated via advanced spectroscopy and microscopic techniques including Raman spectroscopy, FT-IR, XRD, SEM/EDX, and TEM imaging. The Raman spectrum showed D and G bands at 1300 cm^-1 and 1590 cm^-1, respectively, followed by a 2D band at 2770 cm^-1, which confirmed the synthesis of few-layered MDGs. The SEM/EDX data confirmed the presence of 6.15%, 3.17%, and 2.36% of potassium, calcium and magnesium in the obtained MDGs, respectively. Additionally, the FT-IR, XRD, TEM, and SEM data including the plot profile diagrams confirmed the synthesis of MDGs. Further, a computational study was performed for the structural validation of MDGs using Gaussian 09. The density functional theory (DFT) results showed a chemisorption/decoration pattern of doping for metal ions on the few-layered graphene nanosheets, rather than a substitutional pattern. Further, resulting MDGs were used as an active material for the fabrication of a supercapacitor electrode using the polymer gel of PVA-H₃PO₄ as the electrolyte. The fabricated device showed a decent specific capacitance of 18.2 F g^-1 at a scan rate of 5 mV s^-1 with a power density of 1000 W kg^-1 at 5 A g^-1.

Highly conducting polymer electrolyte-ionic liquid and porous carbon material for sandwich electric double layer capacitor

Due to various useful properties of polyethers, the prime objective of present paper is to develop an efficient supercapacitor based on high conducting polymer electrolyte and carbon based materials. To develop such films Polyvinylidene fluoride co-hexafluoropropylene (PVDF-HFP) polymer doped with ionic liquid (IL) 1-ethyl-3-methylimidazolium thiocyanate has been prepared using solution cast technique. The detail studies of polymer electrolyte with optimized value of IL: PVDF-HFP i.e. (80:20) we have reported elsewhere. For electrodes, cobalt enriched porous carbon material has been synthesized and characterized in detail. A sandwiched type electric double layer supercapacitor (EDLC) has been fabricated using maximum conducting polymer-IL film which shows ultra-high capacitance of 294 F/g at room environmental condition. This work successfully demonstrates the suitability of polymer electrolyte in developing highly efficient energy devices.