Low-energy Approach Research Articles

Effect of organic solvent additives on the enhancement of ultrasonic cavitation effects in water for lithium-ion battery electrode delamination

Ultrasonic delamination is a low energy approach for direct recycling of spent lithium-ion batteries. The efficiency of the ultrasonic delamination relies both on the thermophysical properties (such as viscosity, surface tension, and vapour pressure) of the solvent in which the delamination process is carried out, and the properties of the ultrasound source as well as the geometry of the containment vessel. However, the effect of tailoring solutions to optimise cavitation and delamination of battery cathode coatings has not yet been sufficiently investigated. Acoustic detection, high-speed imaging, and sonochemiluminescence (SCL) are employed to study the cavitation processes in water-glycol systems and identify the effect of tailoring solvent composition on cavitation strength. The addition of small volume fractions of organic solvent (ca. 10–30 vol%), including ethylene glycol or glycerol, to the aqueous delamination solution were found to significantly improve the delamination efficiency of lithium-ion battery cathode coatings due to the alteration of these thermophysical properties. However, greater volume fractions of glycol decrease delamination efficiency due to the signal-dampening effect of viscosity on the ultrasonic waves. The findings of this study offer valuable insights for optimising ultrasonic bath solution composition to enhance film delamination processes.

N-oxide connected zwitterionic polyamide nanofiltration membrane for efficient antibiotic/salt separation

Nanofiltration membrane technology for antibiotic desalination in fermentation broth represents a low-energy and high-purity approach. However, it is constrained by the low perm-selectivity and susceptibility to membrane fouling. Here, we develop a novel zwitterionic nanofiltration membrane by incorporating an N-Oxide directly connected zwitterion N,N-bis(3-aminopropyl)methylamine N-oxide (DNMAO) into the nascent polyamide layer via interfacial polymerization. The N-Oxide derived zwitterion created a looser crosslinking network in addition to the trimesoyl chloride-piperazine (TMC-PIP) network, which was supported by Stokes radius related with molecular weight cut-off measurement, and Brunauer-Emmett-Teller Ar adsorption isotherms. Moreover, the directly connected groups (N+-O-) without spacers endow excellent hydration ability and mitigate membrane fouling. The optimized membrane exhibits a water flux of 114.9 L m−2 h−1 and exceptional anti-fouling performance with a flux recovery ratio as high as about 96.4 %. Furthermore, the salt/antibiotic separation factor maintained at 41.1 when continuously filtrating NaCl/erythromycin (ERY) mixed solution for 7 h, which showed a great potential in antibiotic purification.

Multiscale MXene Engineering for Enhanced Capacitive Deionization via Adaptive Surface Charge Tailoring.

Capacitive deionization (CDI), renowned for its eco-friendly and low-energy approach to water treatment, encounters challenges in achieving optimal deionization efficiency and cycle stability despite recent advancements. In this study, the CDI electrodes were crafted with multilevel pore structures using modified cellulose (MCNF) and porous activated MXene (PAMX), aiming to the impact of surface modification on adsorption efficiency, stability, and overall performance. The experimental results demonstrated the superiority of the electrode, specifically the formulation integrating sulfonic acid-treated cellulose and PAMX (SCNF@PAMX). This configuration exhibited remarkably a higher desalination rate (3.91 mg·g-1·min-1) and enhanced desalination capacity (31.24 mg·g-1), with cycling performance exceeding 90%. Density functional theory calculations underscored the formidable adsorption energy of SCNF for Na+ (2.15 eV), surpassing that of other modified electrodes. The enhancement of deionization performance and efficiency through surface charge modification, altering Na+ electrostatic adsorption, lays a solid foundation for advancing more efficient and durable seawater desalination technologies.

Plant-Based Shape Memory Cryogel for Hemorrhage Control.

The escalating global demand for sustainable manufacturing, motivated by concerns over energy conservation and carbon footprints, encounters challenges due to insufficient renewable materials and arduous fabrication procedures to fulfill specific requirements in medical and healthcare systems. Here, biosafe pollen cryogel is engineered as effective hemostats without additional harmful crosslinkers to treat deep noncompressible wounds. A straightforward and low-energy approach is involved in forming stable macroporous cryogel, benefiting from the unique micro-hierarchical structures and chemical components of non-allergenic plant pollen. It is demonstrated that the pollen cryogel exhibits rapid water/blood-triggered shape-memory properties within 2 s. Owing to their inherent nano/micro hierarchical structure and abundant chemical functional groups on the pollen surface, the pollen cryogel shows effective hemostatic performance in a mouse liver penetration model, which is easily removed after usage. Overall, the self-crosslinking pollen cryogel in this work pioneers a framework of potential clinical applications for the first-hand treatment on deep noncompressible wounds.

Sequential high-recovery nanofiltration and electrochemical degradation for the treatment of pharmaceutical wastewater

The presence of antibiotics in aquatic ecosystems poses a significant concern for public health and aquatic life, owing to their contribution to the proliferation of antibiotic-resistant bacteria. Effective wastewater treatment strategies are needed to ensure that discharges from pharmaceutical manufacturing facilities are adequately controlled. Here we propose the sequential use of nanofiltration (NF) for concentrating a real pharmaceutical effluent derived from azithromycin production, followed by electrochemical oxidation for thorough removal of pharmaceutical compounds. The NF membrane demonstrated its capability to concentrate wastewater at a high recovery value of 95 % and 99.7 ± 0.2 % rejection to azithromycin. The subsequent electrochemical oxidation process completely degraded azithromycin in the concentrate within 30 min and reduced total organic carbon by 95 % in 180 min. Such integrated treatment approach minimized the electrochemically-treated volume through a low-energy membrane approach and enhanced mass transfer towards the electrodes, therefore driving the process toward zero-liquid-discharge objectives. Overall, our integrated approach holds promises for cost-effective and sustainable removal of trace pharmaceutical compounds and other organics in pharmaceutical wastewater.

A His bundle pacing protocol for suppressing ventricular arrhythmia maintenance and improving defibrillation efficacy

Background:The excitable gap (EG), defined as the excitable tissue between two subsequent wavefronts of depolarization, is critical for maintaining reentry that underlies deadly ventricular arrhythmias. EG in the His-Purkinje Network (HPN) plays an important role in the maintenance of electrical wave reentry that underlies these arrhythmias. Objective:To determine if rapid His bundle pacing (HBP) during reentry reduces the amount of EG in the HPN and ventricular myocardium to suppress reentry maintenance and/or improve defibrillation efficacy. Methods:In a virtual human biventricular model, reentry was initiated with rapid line pacing followed by HBP delivered for 3, 6, or 9 s at pacing cycle lengths (PCLs) ranging from 10 to 300 ms (n=30). EG was calculated independently for the HPN and myocardium over each PCL. Defibrillation efficacy was assessed for each PCL by stimulating myocardial surface EG with delays ranging from 0.25 to 9 s (increments of 0.25 s, n=36) after the start of HBP. Defibrillation was successful if reentry terminated within 1 s after EG stimulation. This defibrillation protocol was repeated without HBP. To test the approach under different pathological conditions, all protocols were repeated in the model with right (RBBB) or left (LBBB) bundle branch block. Results:Compared to without pacing, HBP for >3 seconds reduced average EG in the HPN and myocardium across a broad range of PCLs for the default, RBBB, and LBBB models. HBP >6 seconds terminated reentrant arrhythmia by converting HPN activation to a sinus rhythm behavior in the default (6/30 PCLs) and RBBB (7/30 PCLs) models. Myocardial EG stimulation during HBP increased the number of successful defibrillation attempts by 3%–19% for 30/30 PCLs in the default model, 3%–6% for 14/30 PCLs in the RBBB model, and 3%–11% for 27/30 PCLs in the LBBB model. Conclusion:HBP can reduce the amount of excitable gap and suppress reentry maintenance in the HPN and myocardium. HBP can also improve the efficacy of low-energy defibrillation approaches targeting excitable myocardium. HBP during reentrant arrhythmias is a promising anti-arrhythmic and defibrillation strategy.

Quantum state transfer on 2D lattices: A low-energy effective Hamiltonian approach

We investigate the transfer of arbitrary single qubit states through a rectangular 2D lattice hosting the isotropic Heisenberg model under a magnetic field along the z direction, where the spin-spin interaction strengths along the vertical sublattices, referred to as rungs, are much stronger than the interactions along other sublattices. Using the rung-rung interaction as perturbation, the model can be mapped to an effective 1D model, and the transfer of low-energy rung states from one rung to another can be represented by a transfer of an arbitrary single-qubit state from one lattice site to another on the 1D effective lattice defined by the effective 1D Hamiltonian. Exploiting this, we propose protocols for transferring arbitrary single-qubit states from one lattice site to another by using specific encoding (decoding) of the single-qubit state into (from) the rung states. We demonstrate that this protocol leads to a quantum advantage in the single-qubit state transfer.

Techno-Economic analysis of an efficient anthocyanin extraction process from grape pomace using eutectic solvents ─ A critical panorama regarding drying techniques and reusability of solvents

A techno-economic analysis of a novel eutectic solvent-based platform useful to recover anthocyanins from grape pomace was performed. The study addressed the economic impact of conventional drying methods and explored the economic implications of purification strategies to separate the extract from the eutectic solvent. This was exemplified by employing solid-phase extraction (SPE) with C18-based adsorbent material. An alternative low-energy demanding approach using SiO2 particles was also assessed for profitability as a freeze-drying replacement strategy. The results highlighted challenges in the economic feasibility of eutectic solvent reusability when conventional SPE is applied, highlighting the need to obtain new and inexpensive bio-based adsorbents. Moreover, it was uncovered that the SiO2-based drying strategy presents itself as a financially viable alternative, effectively addressing the elevated energy requirements associated with conventional drying methods. The findings highlight the potential of alternative solvents-based processes, particularly towards challenges related to the circularity of raw materials.

Green synthesis of biomass-derived porous carbon with hierarchical pores and enhanced surface area for superior VOCs adsorption

The release of volatile organic compounds (VOCs) during the production, storage, and transportation of petroleum and its derivatives can be hazardous to human health and lead to secondary pollution. Addressing this challenge, this study introduces a sustainable and low-energy approach for synthesizing high-efficiency porous carbon materials, leveraging the abundant and renewable watermelon rinds as a carbon source. The carbonization and activation processes were optimized to minimize energy consumption while maximizing adsorptive performance. In this research, watermelon rinds were used as a source of carbon production, and melamine phosphate (FR-MP) was employed as a modifying agent. The FR-MP modified porous biomass-derived activated carbon (PWAC) was created by subjecting it to physical milling, carbonization, and activation. This approach not only utilized a waste biomass effectively but also reduced the overall carbon footprint of the production process. An examination of the effects of FR-MP dosage on the pore structure, surface chemical properties, and VOCs adsorption abilities of PWAC revealed that a higher FR-MP dosage resulted in a wider range of pore sizes within PWAC. The incorporation of FR-MP intensified the development of internal porosity and pore expansion in PWAC. Specifically, the optimized PWAC-0.3 exhibited a significant increase in specific surface area (3149 m²/g) and pore volume (1.76 cm³/g), enhancing adsorption capacities for acetone and n-hexane up to 1046 mg/g and 760 mg/g, respectively. Furthermore, the PWAC demonstrated exceptional recyclability, maintaining 97% of its original adsorption capacity after five cycles, underscoring its sustainable and economic viability. The highly advanced hierarchical ultra-meso-macroporous structure of PWAC significantly reduced the diffusion resistance of VOCs, guaranteeing swift mass transfer and desorption of VOCs. Consequently, the developed PWAC represents a novel, cost-effective, and environmentally-friendly approach for VOCs adsorption, aligning with the principles of green chemistry and low-energy consumption. This research not only provides a promising solution for VOCs mitigation but also highlights the potential of waste biomass in producing high-performance carbon materials.

Chemical freeze-out parameters via a functional renormalization group approach

We study the freeze-out parameters in a QCD-assisted effective theory that accurately captures the quantum and in-medium effects of QCD at low energies. The functional renormalization group approach is implemented in our work to incorporate the nonperturbative quantum, thermal, and density fluctuations. By analyzing the calculated baryon number susceptibility ratios χ2B/χ1B and χ3B/χ2B, we determine the chemical freeze-out temperatures and baryon chemical potentials in cases of hard thermal or dense loop improved μ-dependent gluon potential and μ-independent gluon potential. We calculate the χ4B/χ2B(κσ2) and χ6B/χ2B along the freeze-out line for both cases. It is found that κσ2 exhibits a nonmonotonic behavior in a low collision energy region and approaches one for lower collision energy. χ6B/χ2B shows a similar complicated behavior in our calculation. Published by the American Physical Society 2024

Nanoemulsions: Summary of a Decade of Research and Recent Advances.

Nanoemulsions consist of a combination of several components such as oil, water, emulsifiers, surfactants and cosurfactants. Various techniques for producing nanoemulsions include high-energy and low-energy approaches such as high-pressure homogenization, microfluidization, jet disperser and phase inversion methods. The properties of a formulation can be influenced by elements such as the composition, concentration, size and charge of droplets, which in turn can affect the technique of manufacture. Characterization is conducted by the assessment of several factors such as physical properties, pH analysis, viscosity measurement and refractive index determination. This article offers a thorough examination of the latest developments in nanoemulsion technology, with a focus on their wide-ranging applications and promising future possibilities. It also discusses the administration of nanoemulsions through several methods.

Development and characterization of potential larvicidal nanoemulsions against Aedes aegypti.

Plant-based insecticides offer advantages such as negligible residual effects, reduced risks to both humans and the environment, and immunity to resistance issues that plague conventional chemicals. However, the practical use of monoterpenes in insect control has been hampered by challenges including their poor solubility and stability in aqueous environments. In recent years, the application of nanotechnology-based formulations, specifically nanoemulsions, has emerged as a prospective strategy to surmount these obstacles. In this study, we developed and characterized nanoemulsions based on cymene and myrcene and assessed their toxicity both in vitro using human keratinocytes (HaCAT) cells and in an in vivo model involving Galleria mellonella larvae. Additionally, we investigated the insecticidal efficacy of monoterpenes against the mosquito Aedes aegypti, the primary dengue vector, via larval bioassay. Employing a low-energy approach, we successfully generated nanoemulsions. The cymene-based nanoemulsion exhibited a hydrodynamic diameter of approximately 98 nm and a zeta potential of -25 mV. The myrcene-based nanoemulsion displayed a hydrodynamic diameter of 118 nm and a zeta potential of -20 mV. Notably, both nanoemulsions demonstrated stability over 60 days, accompanied by controlled release properties and low toxicity towards HaCAT cells and Galleria mellonella larvae. Moreover, the nanoemulsions exhibited significant lethality against third-instar Aedes aegypti larvae at a concentration of 50 mg/L. In conclusion, the utilization of nanoemulsions encapsulating cymene and myrcene presents a promising avenue for overcoming the limitations associated with poor solubility and stability of monoterpenes. This study sheds light on the potential of the nanoemulsions as effective and environmentally friendly insecticides in the ongoing battle against mosquito-borne diseases.

Method of smoldering combustion for the treatment of oil sludge-contaminated soil

There is an urgent need to globally remediate oil sludge-contaminated soil (OSS). Smoldering combustion is a new low-energy approach for the treatment of organic waste. Therefore, the feasibility of smoldering combustion for the treatment of OSS was investigated in this study using a series of laboratory-scale experiments. The effective remediation of OSS was found to be achievable when the mass ratio of oil sludge in the sample reached 1/12 and above. Experimental results showed that smoldering at peak temperatures above 500 °C was found to completely remove petroleum hydrocarbons from the samples. The mass ratio of oil sludge in the sample had little effect on the distribution of the major elements (Si, Al, and Ca) in the smoldering products, and most of the minerals in the oil sludge adhered to the surface of the soil particles after smoldering. The smoldering heating environment is detrimental to the reusability of the soil, increases soil pH and available phosphorus content, and decreases organic carbon and total nitrogen content. Moreover, the influence of the airflow rate and material height on smoldering characteristics was investigated. Matching the appropriate airflow rate can help maintain optimal smoldering conditions, and smoldering remains stable with increasing material height. The addition of recovered oil to a sample with a low mass ratio of oil sludge can help with smoldering ignition and improve the removal efficiency of petroleum hydrocarbons. This study has confirmed that smoldering can be used to treat OSS within a broad range of oil sludge concentrations without pretreatment.

Investigating the effect of fusion partners on the enzymatic activity and thermodynamic stability of poly(ethylene terephthalate) degrading enzymes.

Plastics are a cornerstone of the modern world, yet the durable material properties that we have come to depend upon have made them recalcitrant environmental pollutants. Biological solutions in the form of engineered enzymes offer low energy and sustainable approaches to recycle and upcycle plastic waste, uncoupling their production and end of life from fossil fuels and greenhouse gases. These enzymes however, encounter immense challenges acting on plastics: facing hydrophobic surfaces, molecular crowding, and high levels of substrate heterogeneity. There have been mixed reports about the benefits of fusing partner domains to polyethylene terephthalate (PET) degrading enzymes, with moderate improvements identified under specific conditions, but no clarity into the factors that underlie the mechanisms. Here, we use the SpyCatcher003:SpyTag003 technology, which demonstrates a profound 47 °C shift in Tm upon irreversible complex formation, to investigate the influence of the thermal stability of the fusion partner on a range of PETases selected for their optimal reaction temperatures. We find that the thermal stability of the fusion partner does not have a positive correlation on the activity of the enzymes or their evident kinetic and thermal stabilities. Instead, it appears that the fusion to less stable SpyCatcher003 tends to increase the measured activation energy of unfolding compared to the more stable complex and wildtype enzymes. Despite this, the fusions to SpyCatcher003 do not show significantly better catalytic activity on PET films, with or without SpyTag003, and were found to be sometimes disruptive. The approach we highlight here, in using a fusion partner with controllable melting temperature, allowed us to dissect the impact of the stability of a fusion partner on enzyme properties. Although fusion stability did not appear to be coupled with identifiable trends in enzymatic activities, careful analysis of the unfolding pathways, and solid and solution activities of a wider range of enzymes may yield a more detailed understanding.

Low-energy extraction of lignocellulose nanofibers from fresh Musa basjoo pseudo-stem

This study presents a novel approach for the extraction of cellulose nanofibers (CNF) and lignocellulose nanofibers (LCNF) from Musa basjoo pseudo-stems, a relative of bananas, without the need for extensive drying. Instead, wet pseudo-stems were compressed and treated with NaOH solutions at varying temperatures and durations. The extracted material exhibited the characteristic peaks of cellulose I in X-ray diffraction (XRD) patterns, similar to those obtained from dried pseudo-stems. Fourier-transform infrared (FT-IR) spectroscopy confirmed the presence of cellulose I in the treated material and lignocellulose nanofiber clearly shown at 1600-1500, 1421, 1365, and 1161 cm-1. Composition analysis by Van Soest fiber analysis revealed a higher cellulose content in the treated material of wet pseudo-stems compared to that obtained from dried pseudo-stems, indicating the effectiveness of this low-energy extraction method. Meanwhile, field-emission scanning electron microscopy (FE-SEM) images demonstrated clear LCNF in the nanometer scale fibers after NaOH treatment. Overall, this study successfully demonstrated the extraction of LCNF from wet pseudo-stems of Musa basjoo with NaOH treatment at 70°C for 3 hours with 80% extraction result, providing a more efficient and low-energy approach for utilizing waste from Musa basjoo and bananas.

(Invited) Development and Scale-up of Membrane Capacitive Deionization (MCDI) for Desalination and Water Reuse

Desalination and water reuse are the key solutions to address global water scarcity. It is important to recognize the water-energy interactions and develop energy-efficient technologies to separate ions from brackish water, seawater and reclaimed wastewater. Most recently, membrane capacitive deionization (MCDI), inspired by energy storage devices (e.g., supercapacitors), is a promising desalination technology with several advantages of energy efficiency (TDS < 4000 ppm), high water recovery, less chemical additive, and environmental friendliness. In MCDI, ions are electrostatically captured within highly porous carbon electrodes through the formation of electrical double layer during the charging step, and then released into the solution by discharging the electrodes. By incorporating ion-exchange membranes (IEMs) in front of each electrode, the desalination performance can be significantly improved, achieving high salt adsorption capacity and charge efficiency. Over the past few years, we have made efforts to scale up the MCDI stacks for commercialization purposes, which are composed of 32 pairs of 400 mm × 200 mm activated carbon electrodes. Note that a stop-flow operation is applied in the discharge process to increase the water recovery (> 75%). A pilot-scale study of an MCDI system was performed to reclaim the secondary effluents from a municipal wastewater treatment plant. In addition, MCDI prototypes offer promising engineering opportunities for water recycling in high-tech industries, including reverse osmosis reject and wet scrubbing. Furthermore, we will discuss the challenges and perspectives for the future of MCDI as a cost-efficient, low-energy approach for desalination and resource recovery.

NiSe integrated with polymerized reduced carbon sheet: As an effective electrocatalyst for methanol oxidation reaction

A low-energy approach was used to create ternary composites of hollow tubular Poly-N-methyl pyrrole (P-NMPy) and NiSe nanoparticles decorated onreduced graphene oxide (RGO). On the surface of RGO, P-NMPy, and NiSe nanoparticles were uniformly disseminated. The RGO/NiSe@P-NMPy (RNP) polymer nanocomposite was made utilizing a straightforward chemical oxidative process. The RGO/NiSe@P-NMPy nanocomposite was studied using FTIR spectroscopy, UV–visible, XRD, FE-SEM with EDAX, AFM, TEM and electrochemical investigations. The electrocatalytic activity of this polymer nanocomposite for the methanol oxidation reaction in alkaline environments was validated using cyclic voltammetry. The RGO/NiSe@P-NMPy electrocatalyst shows excellent electrocatalytic activity, lower oxidation potential (0.1 V), improved current density (127 mA/cm2), excellent stability and longevity (900 s) towards methanol oxidation reaction (MOR) in alkaline medium. It was observed RGO/NiSe@P-NMPy electrocatalyst, the ECSA value is 70.83 m2/g. This result clearly depicts that RGO/NiSe@P-NMPy electrocatalyst has more active sites for MOR reaction. According to the results, the P-NMPy introduction in RGO/Nickel Selenide structure can enhance the performance of methanol oxidation and increase the resistance to CO in comparison with monometallic catalysts.

Photocatalytic Hydrolysis-A Sustainable Option for the Chemical Upcycling of Polylactic Acid.

Plastic waste is a critical global issue, yet current strategies to avoid committing plastic waste to landfills include incineration, gasification, or pyrolysis high carbon emitting and energy consuming approaches. However, plastic waste can become a resource instead of a problem if high value products, such as fine chemicals and liquid fuel molecules, can be liberated from controlled its decomposition. This letter presents proof of concept on a low-cost, low energy approach to controlled decomposition of plastic, photocatalytic hydrolysis. This approach integrates photolysis and hydrolysis, both slow natural decomposition processes, with a photocatalytic process. The photocatalyst, α-Fe2O3, is embedded into a polylactic acid (PLA) plastic matrix. The photocatalyst/plastic composite is then immersed in water and subjected to low-energy (25 W) UV light for 90 h. The monomer lactide is produced as the major product. α-Fe2O3 (6.9 wt %) was found to accelerate the PLA degradation pathway, achieving 32% solid transformation into liquid phase products, in comparison to PLA on its own, which was found to not decompose, using the same conditions. This highlights a low energy route toward plastic waste upgrade and valorization that is less carbon intensive than pyrolysis and faster than natural degradation. By directly comparing a 25 W (0.025 kWh) UV bulb with a 13 kWh furnace, the photocatalytic reaction would directly consume 520× less energy than a conventional thermochemical pathway. Furthermore, this technology can be extended and applied to other plastics, and other photocatalysts can be used.

Laser-Assisted Design of MOF-Derivative Platforms from Nano- to Centimeter Scales for Photonic and Catalytic Applications.

Laser conversion of metal-organic frameworks (MOFs) has recently emerged as a fast and low-energy consumptive approach to create scalable MOF derivatives for catalysis, energy, and optics. However, due to the virtually unlimited MOF structures and tunable laser parameters, the results of their interaction are unpredictable and poorly controlled. Here, we experimentally base a general approach to create nano- to centimeter-scale MOF derivatives with the desired nonlinear optical and catalytic properties. Five three- and two-dimensional MOFs, differing in chemical composition, topology, and thermal resistance, have been selected as precursors. Tuning the laser parameters (i.e., pulse duration from fs to ns and repetition rate from kHz to MHz), we switch between ultrafast nonthermal destruction and thermal decomposition of MOFs. We have established that regardless of the chemical composition and MOF topology, the tuning of the laser parameters allows obtaining a series of structurally different derivatives, and the transition from femtosecond to nanosecond laser regimes ensures the scaling of the derivatives from nano- to centimeter scales. Herein, the thermal resistance of MOFs affects the structure and chemical composition of the resulting derivatives. Finally, we outline the "laser parameters versus MOF structure" space, in which one can create the desired and scalable platforms with nonlinear optical properties from photoluminescence to light control and enhanced catalytic activity.

Solvent-Free Chemical Recycling of Polymethacrylates made by ATRP and RAFT Polymerization: High-Yielding Depolymerization at Low Temperatures.

Although controlled radical polymerization is an excellent tool to make precision polymeric materials, reversal of the process to retrieve the starting monomer is far less explored despite the significance of chemical recycling. Here, we investigate the bulk depolymerization of RAFT and ATRP-synthesized polymers under identical conditions. RAFT-synthesized polymers undergo a relatively low-temperature solvent-free depolymerization back to monomer thanks to the partial in-situ transformation of the RAFT end-group to macromonomer. Instead, ATRP-synthesized polymers can only depolymerize at significantly higher temperatures (>350 ˚C) through random backbone scission. To aid a more complete depolymerization at even lower temperatures, we performed a facile and quantitative end-group modification strategy in which both ATRP and RAFT end-groups were successfully converted to macromonomers. The macromonomers triggered a lower temperature bulk depolymerization with an onset at 150 ˚C yielding up to 90% of monomer regeneration. The versatility of the methodology was demonstrated by a scalable depolymerization (~10 g of starting polymer) retrieving 84% of the starting monomer intact which could be subsequently used for further polymerization. This work presents a new low-energy approach for depolymerizing controlled radical polymers and creates many future opportunities as high-yielding, solvent-free and scalable depolymerization methods are sought.