Wax from Pyrolysis of Waste Plastics as a Potential Source of Phase Change Material for Thermal Energy Storage

Over the past half-century, plastic consumption has grown rapidly due to its versatility, low cost, and unrivaled functional properties. Among the diff erent implemented strategies for recycling waste plastics, pyrolysis is deemed the most economical option. Currently, the wax obtained from the pyrolysis of waste plastics is mainly used as a feedstock to manufacture chemicals and fuels or added to asphalt for pavement construction, with no other applications of wax being reported. Herein, the thermal pyrolysis of three common waste polyolefin plastics: high-density polyethylene(HDPE), low-density polyethylene(LDPE), and polypropylene(PP), was conducted at 450 ℃. The waste plastics-derived waxes were characterized and studied for a potential new application: phase change materials(PCMs) for thermal energy storage(TES). Gas chromatography–mass spectrometry analysis showed that paraffin makes up most of the composition of HDPE and LDPE waxes, whereas PP wax contains a mixture of naphthene, isoparaffin, olefin, and paraffin. Diff erential scanning calorimetry(DSC) analysis indicated that HDPE and LDPE waxes have a peak melting temperature of 33.8 ℃ and 40.3 ℃, with a relatively high latent heat of 103.2 J/g and 88.3 J/g, respectively, whereas the PP wax was found to have almost negligible latent heat. Fourier transform infrared spectroscopy and DSC results revealed good chemical and thermal stability of HDPE and LDPE waxes after 100 cycles of thermal cycling. Performance evaluation of the waxes was also conducted using a thermal storage pad to understand their thermoregulation characteristics for TES applications.

Polymer electrolytes for flexible zinc-air batteries:Recent progress and future directions

This review article delves into the development of electrolytes for flexible zinc-air batteries(FZABs),a critical component driving the advancement of flexible electronics.We started by surveying the current advancements in electrolyte technologies,including solid-state and gel-based types,and their contributions to enhance the flexibility,efficiency,and durability of FZABs.Secondly,we explored the challenges in this domain,focusing on maintaining electrolyte stability under mechanical stress,ensuring compatibility with flexible substrates,optimizing ion conductivity,and under harsh environmental conditions.Furthermore,the key issues regarding interface details between electrolyte and the electrodes are covered as well.We then discussed the future of electrolyte development in FZABs,highlighting potential avenues such as materials development,sustainability,in-situ studies,and battery integration.This review offers an in-depth overview of the advancements,challenges,and potential breakthroughs in creating electrolytes for FZABs over the past five years.It serves as a guide for both researchers and industry professionals in this dynamic area.

Baiting bacteria with amino acidic and peptidic corona coated defect-engineered antimicrobial nanoclusters for optimized wound healing

Keeping steps ahead of the bacteria in the race for more efficacious antibacterial strategies is increasingly difficult with the advent of bacterial resistance genes.Herein,we engineered copper sulfide nanoclusters(CuS_(x) NCs)with variable sulfur defects for enhanced dual-treatment of bacterial infections by manipulating photothermal effects and Fenton-like activity.Next,by encasing CuS_(x) NCs with a complex mixture of amino acids and short peptides derived from Luria-Bertani bacterial culture media as a protein corona,we managed to coax E.Coli to take up these CuS_(x) NCs.As a whole,Amino-Pep-CuS_(x) NCs was perceived as a food source and actively consumed by bacteria,enhancing their effective uptake by at least 1.5-fold greater than full length BSA protein BSA-corona CuS_(x) NCs.Through strategically using defect-engineering,we successfully fine-tune photothermal effect and Fenton-like capacity of CuS_(x) NCs.Increased sulfur defects lead to reduced but sufficient heat generation under solar-light irradiation and increased production of toxic hydroxyl radicals.By fine-tuning sulfur defects during synthesis,we achieve CuS_(x) NCs with an optimal synergistic effect,significantly enhancing their bactericidal properties.These ultra-small and biodegradable CuS_(x) NCs can rapidly break down after treatment for clearance.Thus,Amino-Pep-CuS_(x) NCs demonstrate effective eradication of bacteria both in vitro and in vivo because of their relatively high uptake,optimal balanced photothermal and chemodynamic outcomes.Our study offers a straightforward and efficient method to enhance bacterial uptake of next generation of antibacterial agents.

Erratum to:Polymer electrolytes for flexible zinc-air batteries:Recent progress and future directions

Erratum to Nano Research,2024,17(7):6058-6079 https://doi.org/10.1007/s12274-024-6555-z The name and affiliation of the seventh author,Janet Beng Hoon Tan,were incorrectly labeled.The corrections have been made to the online version of the original article.

Face Masks in the New COVID-19 Normal: Materials, Testing,and Perspectives

The increasing prevalence of infectious diseases in recent decades has posed a serious threat to public health.Routes of transmission differ,but the respiratory droplet or airborne route has the greatest potential to disrupt social intercourse,while being amenable to prevention by the humble facemask.Different types of masks give different levels of protection to the user.The ongoing COVID-19 pandemic has even resulted in a global shortage of face masks and the raw materials that go into them,driving individuals to self-produce masks from household items.At the same time,research has been accelerated towards improving the quality and performance of face masks,e.g.,by introducing properties such as antimicrobial activity and superhydrophobicity.This review will cover mask-wearing from the public health perspective,the technical details of commercial and home-made masks,and recent advances in mask engineering,disinfection,and materials and discuss the sustainability of mask-wearing and mask production into the future.

Flexible polymeric patch based nanotherapeutics against non-cancer therapy

Flexible polymeric patches find widespread applications in biomedicine because of their biological and tunable features including excellent patient compliance,superior biocompatibility and biodegradation,as well as high loading capability and permeability of drug.Such polymeric patches are classified into microneedles(MNs),hydrogel,microcapsule,microsphere and fiber depending on the formed morphology.The combination of nanomaterials with polymeric patches allows for improved advantages of increased curative efficacy and lowered systemic toxicity,promoting on-demand and regulated drug administration,thus providing the great potential to their clinic translation.In this review,the category of flexible polymeric patches that are utilized to integrate with nanomaterials is briefly presented and their advantages in bioapplications are further discussed.The applications of nanomaterials embedded polymeric patches in non-cancerous diseases were also systematically reviewed,including diabetes therapy,wound healing,dermatological disease therapy,bone regeneration,cardiac repair,hair repair,obesity therapy and some immune disease therapy.Alternatively,the limitations,latest challenges and future perspectives of such biomedical therapeutic devices are addressed.

Current Research Trends and Perspectives on Solid-State Nanomaterials in Hydrogen Storage

Hydrogen energy,with environment amicable,renewable,efficiency,and cost-effective advantages,is the future mainstream substitution of fossil-based fuel.However,the extremely low volumetric density gives rise to the main challenge in hydrogen storage,and therefore,exploring effective storage techniques is key hurdles that need to be crossed to accomplish the sustainable hydrogen economy.Hydrogen physically or chemically stored into nanomaterials in the solid-state is a desirable prospect for effective large-scale hydrogen storage,which has exhibited great potentials for applications in both reversible onboard storage and regenerable off-board storage applications.Its attractive points include safe,compact,light,reversibility,and efficiently produce sufficient pure hydrogen fuel under the mild condition.This review comprehensively gathers the state-of-art solid-state hydrogen storage technologies using nanostructured materials,involving nanoporous carbon materials,metal-organic frameworks,covalent organic frameworks,porous aromatic frameworks,nanoporous organic polymers,and nanoscale hydrides.It describes significant advances achieved so far,and main barriers need to be surmounted to approach practical applications,as well as offers a perspective for sustainable energy research.

The Efficacy of Plant-Based Ionizers in Removing Aerosol for COVID-19 Mitigation

Small-sized droplets/aerosol transmission is one of the factors responsible for the spread of COVID-19,in addition to large droplets and surface contamination(fomites).While large droplets and surface contamination can be relatively easier to deal with(i.e.,using mask and proper hygiene measures),aerosol presents a different challenge due to their ability to remain airborne for a long time.This calls for mitigation solutions that can rapidly eliminate the airborne aerosol.Pre-COVID-19,air ionizers have been touted as effective tools to eliminate small particulates.In this work,we sought to evaluate the efficacy of a novel plant-based ionizer in eliminating aerosol.It was found that factors such as the ion concentration,humidity,and ventilation can drastically affect the efficacy of aerosol removal.The aerosol removal rate was quantified in terms of ACH(air changes per hour)and CADR-(clean air delivery rate-)equivalent unit,with ACH as high as 12 and CADR as high as 141 ft^(3)/minute being achieved by a plant-based ionizer in a small isolated room.This work provides an important and timely guidance on the effective deployment of ionizers in minimizing the risk of COVID-19 spread via airborne aerosol,especially in a poorly-ventilated environment.