Inert Polymer Research Articles

Tailoring the Interfacial Interactions of Porous Polymer Membranes to Accelerate Atomic Layer Deposition: The Latent Path to Antifouling Membranes

Atomic layer deposition (ALD) is a powerful strategy to engineer hybrid organic-inorganic membranes with emergent functionalities. The combination of atomic-level thickness control, wide materials palette, and unprecedented conformality allow the physiochemical properties (e.g., hydrophilicity) of mesoporous polymer membranes to be precisely tuned. The nucleation of ALD materials growth on polymer surfaces relies on chemical interactions between the ALD metalorganic precursor and functional groups in the polymer structure and these interactions dictate the number of ALD cycles required to achieve a continuous coating. Strategies to enhance these interactions could enable desirable properties such as anti-fouling behavior to be imparted on inert polymer surfaces that lack the necessary functional groups for ALD nucleation. In this study, we demonstrate that the reactivity of polyacrylonitrile (PAN) membranes towards ALD metal oxide (MO) precursors with Lewis acid characteristics is enhanced by introducing Lewis base functional groups (amidoxime: Am) on the PAN backbone. The resulting Lewis acid-base interactions accelerates the MO nucleation in Am-PAN and reduce the number of deposition cycles required to achieve hydrophilicity compared to the untreated PAN membrane. Unveiling the reaction mechanism, the in-situ FTIR intensity changes established enhanced interaction dynamics between the ALD MO precursors and the Am-PAN membrane, unlike the PAN membrane. For similar MO cycles, through both spectroscopic and thermogravimetric analysis, we observe enhanced MO loading in the Am-PAN membrane compared to the PAN membrane. Here we have verified that strong Lewis acid-base interactions led to enhanced loading for a range of ALD MO materials including Al2O3, TiO2, SnO2, and ZnO. Most importantly, the Al2O3-Am-PAN hybrid membrane showed 23.3% higher antifouling capability compared to the pristine PAN membrane. Our approach expands the scope of design options for fouling-resistant porous hybrid inorganic-organic membranes and may reduce manufacturing costs of water treatment membranes.

Tannic acid-aminopropyltriethoxysilane co-deposition modified polymer membrane for α-glucosidase immobilization

Mussel-inspired catechol-amine co-deposition is an effective modification strategy for various materials. In this work, polyvinylidene fluoride (PVDF) membrane was employed as the carrier for α-glucosidase immobilization. By virtue of the co-polymerization of tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) and the hydrolysis of APTES, a hierarchical layer-colloidal nanospheres coating was decorated on the surface of PVDF membrane. Subsequently, α-glucosidase was covalently bound to the modified PVDF membrane through Schiff base reaction and Michael addition reaction between the residual quinine groups in the coating and the amino groups in enzyme molecules. Several parameters affecting the immobilization procedure were investigated thoroughly. The morphology and functional groups of the prepared composite were characterized by scanning electron microscopy (SEM), Fourier transform infrared-Attenuated total reflectance spectroscopy (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS). Combined with capillary electrophoresis (CE) analysis, the performance, enzyme reaction kinetics and inhibition kinetics of PVDF-immobilized α-glucosidase were studied. The immobilized enzyme exhibited the enhanced tolerance to temperature and pH value. In addition, it possessed good reusability maintaining 77.1% of initial relative activity after 11 recycles, and batch-to-batch reproducibility with RSD of 4.3% (n = 10). The Michaelis-Menten constant (Km) of immobilized enzyme was calculated to be 4.16 mM, and IC50 value of acarbose was 0.10 µM. Finally, the PVDF-immobilized α-glucosidase was applied to screening potential inhibitors from 13 kinds of traditional Chinese medicines (TCMs), among which Sanguisorba Radix exhibited the strongest inhibitory activity. The positive results suggested that TA/APTES co-deposition was a simple and mild functionalization method for chemically inert polymer membrane and the proposed screening method was a reliable approach for discovering enzyme inhibitors from TCMs.

Hydro/Organo/Ionogels: "Controllable" Electromagnetic Wave Absorbers.

Demand for electromagnetic wave (EMW) absorbers continues to increase with technological advances in wearable electronics and military applications. In this study, a new strategy to overcome the drawbacks of current absorbers by employing the co-contribution of functional polymer frameworks and liquids with strong EMW absorption properties is proposed. Strongly polar water, dimethyl sulfoxide/water mixtures, and highly conductive 1-ethyl-3-methylimidazolium ethyl sulfate ([EMI][ES]) are immobilized in dielectrically inert polymer networks to form different classes of gels (hydrogels, organogels, and ionogels). These gels demonstrate a high correlation between their dielectric properties and polarity/ionic conductivity/non-covalent interaction of immobilized liquids. Thus, the EMW absorption performances of the gels can be precisely tuned over a wide range due to the diversity and stability of the liquids. The prepared hydrogels show good shielding performance (shielding efficiency > 20dB) due to the high dielectric constants, while organogels with moderate attenuation ability and impedance matching achieve full-wave absorption in X-band (8.2-12.4GHz) at 2.5 ± 0.5mm. The ionogels also offer a wide effective absorption bandwidth (10.79-16.38GHz at 2.2mm) via prominent ionic conduction loss. In short, this work provides a conceptually novel platform to develop high-efficient, customizable, and low-cost functional absorbers.

Nanocomposite Membranes Based on Fluoropolymers for Electrochemical Energy Sources.

The physicochemical and transport properties (ion-exchange capacity, water content, diffusion permeability, conductivity, and current-voltage characteristic) of a series of perfluorinated membranes with an inert fluoropolymer content from 0 to 40%, obtained by polymer solution casting, were studied. Based on the analysis of the parameters of the extended three-wire model, the effect of an inert component on the path of electric current flow in the membrane and its selectivity were estimated. The mechanical characteristics of the membranes, such as Young’s modulus, yield strength, tensile strength, and relative elongation, were determined from the dynamometric curves. The optimal amount of the inert polymer in the perfluorinated membrane was found to be 20%, which does not significantly affect its structure and electrotransport properties but increases the elasticity of the obtained samples. Therefore, the perfluorinated membrane with 20% of inert fluoropolymer is promising for its application in redox flow batteries and direct methanol fuel cells.

Binding and stability properties of PEG2000 to globular proteins: The case of lysozyme

• Lysozyme-PEG interaction was studied using calorimetry and spectroscopic techniques. • A PEG/lysozyme interaction in the low polymer concentration regime occurs. • The interaction process is weak, and it is entropically driven. • At low concentration, PEG induces an increase of the denaturation temperature. Poly(ethylene glycol) is a linear polymer widely used in many biotechnological and industrial applications. It is thought that PEG is an inert polymer and its effect on protein stability and dynamics is essentially due to the excluded volume effect which depends on its concentration. However, increasing evidence suggests that direct interactions can be established between PEG and proteins. With the aim to shed more light on PEG-protein interactions, this work evaluated the enthalpy pair interaction coefficient and the enthalpy cross-interaction coefficient for the system PEG2000-lysozyme. In addition, using calorimetry and spectroscopy, the binding, the stability and the conformational behaviour of lysozyme were evaluated in the low polymer concentration regime. We found that a weak interaction between lysozyme and PEG occurs with a binding constant of 1600 ± 230 M −1 . The interaction process is mainly entropically driven: the release of water molecules associated to protein surface and polymer chains may account for this phenomenon. In addition, we found that the general lysozyme structure was only marginally affected by PEG interaction. A small but significant increase in the denaturation temperature was observed most likely due to weak interactions with the polymer and to the dehydration of protein surface.

The Latest Developments in Radiation-Grafted Anion-Exchange Polymer Electrolytes for Low Temperature Electrochemical Systems

Anion-exchange membranes (AEM) are being developed for use in electrochemical technologies including fuel cells (AEMFC),water electrolysis (AEMWE for green hydrogen), electrolysers for CO2 reduction (CO2RR), and reverse electrodialysis (RED). Radiation-grafted AEMs (RG-AEM) represent a promising class of AEM that can exhibit high conductivities (OH- conductivities of > 200 mS cm-1 at temperatures above 60 °C) and favourable in situ water transport characteristics). Hence, RG-AEMs have shown significant promise when tested in AEMFCs alongside powdered radiation-grafted anion-exchange ionomers (RG-AEI), producing high performances and promising durabilities [Energy Environ. Sci., 12, 1575 (2019) and Nature Commun., 11, 3561 (2020)], even at temperatures above 100 °C [Dekel et al., J. Power Sources Adv., 5, 100023 (2020)].An Achilles heel with RG-AEM types is that they can swell excessively in water and have large dimensional changes between the dehydrated and hydrated states. This limits the ion-exchange capacities (IEC) that can be used: excessive IECs in RG-AEM will cause excessive swelling and poorer robustness. This clearly indicates that additional crosslinking is needed. As Kohl et al. have highlighted, optimised crosslinking can lead to production of high-IEC AEMs that are both robust enough to be < 20 µm in thickness and also low swelling [e.g. J. Electrochem. Soc., 166, F637 (2019)], allowing truly world-leading AEMFC performances.RG-AEMs are also being used as a screening platform for down-selecting different (cationic) head-group chemistries for use in RED cells (a salinity gradient power technology), where different head-groups may lead to different AEM characteristics such as: in-cell resistance (when in contact with aqueous electrolytes), permselectivity, and fouling characteristics (when real world waters such as industrial brines, seawater and freshwater are used). It was evident very early on in these studies that RG-AEMs (desirably) exhibit extremely low resistances but also (undesirably) very low permselectivities when un-crosslinked (less than the required 90%+ permselectivity). Our work on RG-type cation-exchange membranes [Sustainable Energy Fuels, 3, 1682 (2019)] clearly shows that introduction of crosslinking can improve permselectivity.Crosslinking always involves a compromise, where its introduction can improve a membrane characteristic (e.g. reduced swelling or improved permselectivity) but also leads to lower conductivities or poorer transport of chemical species through the membranes. Hence, crosslinking types and levels need to be carefully controlled. With RG-AEMs (made by electron-beam activation (peroxidation) of inert polymer films, followed by grafting of monomers and post-graft amination), we have a choice of introducing crosslinking at various stages. The figure below summarises the two different approaches to crosslinking that will be discussed in the presentation: adding a divinyl-type crosslinker into the grafting mixture or adding a diamine-type crosslinker into the amination step.This presentation will present a selection of recent RG-AEM and RG-AEI developments from a number of projects:(1) REDAEM: AEMs for RED cells [EPSRC Grant EP/R044163/1];(2) CARAEM: Novel RG-AEMs for AEMFCs and AEMWE [EPSRC Grant EP/T009233/1];(3) SELECTCO2: RG-AEMs being tested in CO2RR cells [EU Horizon 2020 grant agreement 851441].This presentation will show:(a) RG-AEMs made from thin high density polyethylene (HDPE) precursors appear better for application in AEMFCs, while RG-AEMs from made from thicker ETFE precursors appear to be better for CO2RR cells and RED;(b) RG-AEMs can be made using a variety of crosslinking strategies;(c) RG-AEIs can be made using ETFE powders and give optimal performance after cryogrinding down to micrometer sizes; Figure 1

When Electronically Inert Polymers Meet Conjugated Polymers: Emerging Opportunities in Organic Photovoltaics

When Electronically Inert Polymers Meet Conjugated Polymers: Emerging Opportunities in Organic Photovoltaics

Continuous liquid interface production of 3D printed drug-loaded spacers to improve prostate cancer brachytherapy treatment

Brachytherapy, which is the placement of radioactive seeds directly into tissue such as the prostate, is an important curative treatment for prostate cancer. By delivering a high dose of radiation from within the prostate gland, brachytherapy is an effective method of killing prostate cancer cells while limiting radiation dose to normal tissue. The main shortcomings of this treatment are: less efficacy against high grade tumor cells, acute urinary retention, and sub-acute urinary frequency and urgency. One strategy to improve brachytherapy is to incorporate therapeutics into brachytherapy. Drugs, such as docetaxel, can improve therapeutic efficacy, and dexamethasone is known to decrease urinary side effects. However, both therapeutics have high systemic side effects. To overcome this challenge, we hypothesized that we can incorporate therapeutics into the inert polymer spacers that are used to correctly space brachytherapy seeds during brachytherapy to enable local drug delivery. To accomplish this, we engineered 3D printed drug-loaded brachytherapy spacers using continuous liquid interface production (CLIP) with different surface patterns to control drug release. These devices have the same physical size as existing spacers, allowing them to easily replace commercial spacers. We examined these drug-loaded spacers using docetaxel and dexamethasone as model drugs in a murine model of prostate cancer. We found that drug-loaded spacers led to higher therapeutic efficacy for brachytherapy, and there was no discernable systemic toxicity from the drug-loaded spacers. Statement of significanceThere has been high interest in the application of 3D printing to engineer novel medical devices. However, such efforts have been limited by the lack of technologies that can fabricate devices suitable for real world medical applications. In this study, we demonstrate a unique application for 3D printing to enhance brachytherapy for cancer treatment. We engineered drug-loaded brachytherapy spacers that can be fabricated using Continuous Liquid Interface Production (CLIP) 3D printing, allowing tunable printing of drug-loaded devices, and implanted intraoperatively with brachytherapy seeds. In combined chemotherapy and brachytherapy we are able to achieve greater therapeutic efficacy through local drug delivery and without systemic toxicities. We believe our work will facilitate further investigation in medical applications of 3D printing.

818-P: Chronic Oral Polymeric Duodenal Exclusion Therapy Has Profound Metabolic Benefits in a T2D Rat Model and Affects Duodenal Morphological Enteroplasticity Similar to RYGB surgery: Implications for T2D Therapy

Background: RYGB surgery has significant weight loss and improvement in glycemia, attributed predominantly to duodenal exclusion. To mimic this effect non-invasively, we developed oral, gut-restricted, inert polymer (GLY-POL) that interacts with mucus in the proximal small intestine to form a dynamic barrier excluding the duodenal lining from luminal contents. We hypothesized that such treatment would result in significant metabolic improvement and affect morphologic enteroplasticity similar to RYGB. Methods: Goto-kakizaki (GK) rats were gavaged with GLY-POL daily for 8-weeks (n=7 per group) . Metabolic responses were evaluated weekly (BW, food intake, oGTT, mMTT, HOMA-IR) . Duodenal morphometric analysis (villus height and crypt depth) was performed in excised duodenum after study completion. Results: There was profound metabolic improvement with chronic GLY-POL therapy; oGTT (iAUC ↓ = 60 - 70%, p&amp;lt;0.0005) , mMTT (iAUC ↓ &amp;gt; 55%, p &amp;lt; 0.005) , HOMA-IR improvement (p&amp;lt;0.005) , 6% weight loss (p&amp;lt;0.005) . There was no difference in food intake between the groups. There was a significant reduction in the duodenal villus height (p&amp;lt;0.0001) and crypt depth (p&amp;lt;0.0001) in treated rats compared to controls. Conclusion: Our results confirm a key role for chronic duodenal exclusion oral GLY-POL therapy in improving the systemic metabolic milieu with profound reduction in FPG, PPG, insulin resistance and weight loss. Duodenal villus morphological changes are likely due to nutritional depletion from the GLY-POL lining. Similar cellular structural changes have been reported in the bypassed portion of the small intestine after RYGB surgery. GLY-POL therapy offers the potential for a novel non-invasive approach for glycemic and weight control in T2D patients that mimics the effects of gastric bypass without the adverse effects associated with this surgery. Disclosure A.Nimgaonkar: Employee; Glyscend Inc. M.Fineman: None. T.H.Jozefiak: Employee; Glyscend Inc., Stock/Shareholder; Glycologix, LLC. F.Guerina: Employee; Glyscend Inc. S.L.Kelleher: Research Support; Glyscend Inc. T.Carlson: Employee; Glyscend Inc. K.Colbert: Stock/Shareholder; Glyscend Inc., LifeSprout. S.Polomoscanik: None. J.S.Petersen: None. K.M.Habegger: Consultant; Glyscend Inc., Research Support; Eli Lilly and Company, Novo Nordisk, Stock/Shareholder; Glyscend Inc. P.J.Pasricha: Consultant; Vanda, Other Relationship; Teva Pharmaceutical Industries Ltd., Stock/Shareholder; Glyscend Inc., Neurogastrx, P4M.

3D printing of compact electrochemical cell for sequential analysis of steroid hormones

3D printing technology revolutionized the development of electrochemical sensors allowing the fabrication of custom devices that can be adapted to meet specific applications. This study describes the development of a miniaturized electrochemical cell containing integrated electrodes manufactured entirely by 3D printing for the sequential detection of steroid hormones. The electrochemical sensor was manufactured in a single step by combining two types of thermoplastic filaments. Polylactic acid-Carbon Black (PLA-CB) was used in the electrode region and acrylonitrile butadiene styrene (ABS) was used in the insulating region. Chemical/electrochemical treatments were used to remove the inert polymer matrix and expose the electroactive sites of the CB electrodes. These pre-treatment procedures significantly enhanced the electrochemical response of the printed sensor. The analytical performance of the activated 3D printed electrochemical cell was demonstrated in the sequential detection of estradiol (E2) and progesterone (P4) in artificial urine. The electrochemical cell offered good repeatability (RSD = 3.1%) and reproducibility (RSD = 10.7%) between analyses reaching detection limits of 0.11 and 17.8 µmol L-1 for E2 and P4, respectively. In this sense, these results demonstrate that the use of 3D printing paves the way for the fast and economical fabrication of miniaturized electrochemical cells for hormone detection in biological fluids.

Crosslinking inert liquidlike polydimethylsiloxane brushes using bis-diazirine chemical insertion for enhanced mechanical durability

Inert polymer brushes offer excellent omniphobic and antifouling properties but enhancing their durability remains a challenge, since their chemical inertness also means they lack the functionality necessary for traditional crosslinking reactions. We report the crosslinking of nanoscale polydimethylsiloxane (PDMS) brushes on surfaces through a chemically non-destructive C–H insertion. bis-Diazirine crosslinkers are employed to covalently link methyl groups (i.e., insertion into Si–C–H bonds) along neighboring PDMS chains upon thermal activation. The successful crosslinking of PDMS brushes is evidenced directly by X-ray photoelectron spectroscopy analysis and indirectly through mechanical durability characterization using Martindale abrasion. The apparent contact angles and low contact angle hysteresis of crosslinked PDMS brushes are well-maintained post abrasion, indicating enhanced mechanical durability as compared to uncrosslinked brushes. The longevity of the liquidlike character of crosslinked PDMS brushes is also improved following mechanical wear, with a shear ice adhesion strength half that of uncrosslinked brush surfaces. The crosslinked surfaces are also resistant to acid corrosion, heating, sonication, and tape peeling, indicating that the physicochemical stability of PDMS brushes is not degraded upon crosslinking. Finally, crosslinked brushes are additionally deposited on polycarbonate substrates, and the optical transparency, enhanced durability, and droplet shedding capability of the coated substrates are demonstrated. Overall, this study provides a new pathway for the design of durable inert nanoscale coatings that maintain their attractive surface properties after mechanical wear.

Lamprey-Teeth-Inspired Oriented Antibacterial Sericin Microneedles for Infected Wound Healing Improvement.

The therapeutic efficacy of wound infections caused by bacteria is challenged by limited wound repairs and a high risk of inflammation. Microneedles have been generated for wound healing since they are able to efficiently pierce the epidermis and deliver drugs. However, regular microneedles cannot provide oriented traction to "shrink" the wound area, and most microneedles are made of inert polymers, which mainly serve as a support but rarely participate in the following physiological processes. Herein, inspired by lamprey teeth, we designed oriented antibacterial sericin microneedles with dually functionalized needles to provide penetration and directional traction. Sericin, derived from silkworm cocoons, was employed to fabricate microneedle tips, significantly improving skin repair via hair follicle regeneration and angiogenesis. Besides, zinc oxide nanoparticles were integrated as an antibacterial module, endowing the OASM with high bacterial suppression. It is believed that the synergy of these systems may effectively heal infected wounds, suggesting its clinically translational potential.

A facile method for grafting functional hydrogel films on PTFE, PVDF, and TPX polymers.

The use of polymeric materials in biomedical applications requires a judicious control of surface properties as they are directly related to cellular interactions and biocompatibility. The most desired chemical surface properties include hydrophilicity and the presence of functional groups for surface modification. In this work, we describe a method to graft a highly stable, ultra-thin, amine-functional hydrogel layer onto highly inert surfaces of poly(tetrafluoroethylene) (PTFE), poly(vinylidene fluoride) (PVDF), and poly(4-methyl-1-pentene) (PMP or TPX). Covalent grafting is realized with hydrophilic poly(vinylamine-co-acetamide)s by C-H insertion crosslinking (CHic) chemistry initiated by UV light. These polyvinylamides carry tetrafluorophenyl azide groups as photo or thermo activated binding sites and contain further free amine groups, which can be used to bind peptides such as biological ligands, polysaccharides, or other hydrogel layers. The covalently bound surface layers resist intensive Soxhlet extraction confirming the stability of the coating. Fluorescent staining verified the accessibility of free primary amine groups, which can be used for the functionalization of the surface with bioactive molecules. The coating demonstrates hydrophobic wetting behavior when conditioned in air and hydrophilic wetting behavior when conditioned in water showing the presence of loosely crosslinked polymer chains that can re-orient. We believe that the reported application of CHic for the surface modification of fluorinated polymers like PTFE and PVDF as well as TPX can form the basis for advanced biocompatible and biofunctional surface engineering.

Preparation and structure tuning of CO2 adsorbent based on in-situ amine-functionalized hierarchical porous polymer

Amine-functionalized porous adsorbent is one kind of important materials in carbon dioxide capture due to its stability and efficiency. In this study, a copolymer (polyHIPE) with interconnected macropore networks, hierarchical porous structure and abundant branched amino groups was prepared by high internal phase emulsion (HIPE) strategy via copolymerization of styrene (St), divinylbenzene (DVB), tetraethyl orthosilicate (TEOS), and triethoxyvinylsilane (VTEO), and then a novel amine-functionalized CO 2 adsorbent was synthesized by in situ ring-opening grafting copolymerization of aziridine with the polyHIPE. The structure, morphology, and physicochemical properties of the polyHIPEs were characterized by FTIR, TEM, TGA, and SEM. The key roles of VTEO and TEOS in introducing active hydroxyl groups onto the surface of the inert polymer was evaluated, which was essential to improve the hydrophilicity of the polyHIPE and to provide reactive sites to combine with amine agents. The contact angle of the polyHIPE while copolymerized with TEOS and VTEO significantly was decreased from 144° to 72°. In order to further increase the specific surface area of the polyHIPEs, post crosslinking of polyHIPEs was implemented through a Friedel–Crafts reaction. The specific surface area of post-crosslinked polyHIPE could reach 513 m 2 /g, which was proven to be effective to enhance its CO 2 adsorption capacity. Finally, the abundant branched amino sites via aziridine grafting and high surface area greatly enhanced CO 2 adsorption capacity of the amino-modified polyHIPEs. The adsorption capacity of 2.40 and 3.25 mmol CO 2 /g could be achieved under dry and humid conditions in 0.1 atm partial pressure of CO 2 , respectively. • The hydroxyl groups modified monolithic was synthesized by one-step high inner phase emulsion copolymerization. • The post-crosslinking and in-situ grafting of amino obtained higher specific surface area and more CO 2 adsorption sites. • The polyHIPE-V 1 T 2 -HCP-NH monolithic exhibits obviously high CO 2 adsorption capacity and amino efficiency. • 3.25 mmol CO 2 /g-adsorbent and amine efficiency of 0.65 mmol CO 2 /mmol N could be achieved under humid conditions.

Мікропластик як глобальне джерело забруднення навколишнього середовища

In the work, a comprehensive analysis of the accumulation of microplastic in natural and technical objects: World Ocean, surface waters, soils, agrochemicals, food products has been carried out, its direct and indirect negative impact on human health and biota, soil destruction and disruption of the normal functioning of ecological systems are noted. It has been established that the uncontrolled production of plastics leads to mass pollution not only of the equator of the World Ocean, but also to the formation of microplastics sediment on the bottom of the ocean. It is noted that chemically inert polymers contain toxic chemicals/additives: flame retardants, plasticizers, UV stabilizers, antimicrobial additives and solvents. Their toxic effect on certain organisms has not been studied in detail and poses a potential threat to human health and marine fauna. Recently, the widespread use of microplastic in the countries of the European Economic Area in agriculture, which is used to cover toxic pesticides and fertilizers, has been noted. Such use accounts for 65 % of the total microplastic pollution in these countries, which is 4—23 times more than the pollution of the world's oceans. Microplastic poses a potential threat to the health of farmers, has a negative impact on soil structure, climate, food quality, and existing ecosystems. Taking into account the size of microplastic from 1 mm to 1 μm, its determination by traditional methods is impossible. For this, the method of Dynamic Laser Scattering (DLS) is effectively used, which makes it possible to determine the dispersion, size of particles and their distribution in the solution by individual fractions. The method of thermal and catalytic low-temperature pyrolysis of plastic/microplastic waste disposal is considered, which allows them to be effectively processed into environmentally safe and renewable energy resources.

Impact of band-engineered polymer-interlayers on heterojunction solar cells based on 2D-layered perovskites (Cs3Sb2ClxI9−x)

Thin-film formation process of Cs3Sb2ClxI9−x perovskite in its 2D layered-form is complex and provides a poor control over film-morphology and results in a rough film-surface. Such a surface prompts formation of recombination centers for photogenerated carriers at the interface between the active and carrier-transport layers. We report a process of interface-engineering to decrease recombination loss and thereby improve photovoltaic parameters. Apart from using an inert polymer layer to improve the surface morphology of Cs3Sb2ClxI9−x thin-films, we have introduced transition metal dichalcogenide (TMD) nanoflakes into the polymer; the hybrid interlayer (polymer:TMD) between the active perovskite layer and an electron-transport layer (ETL) could increase the recombination resistance without affecting the series resistance of devices, leading to an increase in photovoltaic properties. We have employed atomic force microscopy and Kelvin probe force microscopy to probe the perovskite surface. Current-voltage characteristics and impedance spectroscopy of the devices were recorded to derive their recombination and series resistances upon the interface-engineering process. Band-diagram of the devices based on Cs3Sb2ClxI9−x/polymer:TMD/ETL have been drawn from scanning tunneling spectroscopy and differential tunnel conductance thereof. The heterojunction devices with a type-II band-alignment at the interfaces have resulted in an enhanced photovoltaic performance in Cs3Sb2ClxI9−x-based solar cells with a PCE of 3.42%.

Inert polymer modification of an exciplex emitter enhances the light-emitting efficiency and reduces the efficiency roll-off of solution-processed organic light-emitting diodes

The maximum external quantum efficiency of the solution-processed OLEDs is increased from 3.71% to 4.77% and the efficiency roll-off is reduced from 31.5% to 10.7% at 5000 cd m−2by introducing inert PS in the exciplex emissive layer.

Rapid Functionalization of Polytetrafluorethylene (PTFE) Surfaces with Nitrogen Functional Groups.

The biocompatibility of body implants made from polytetrafluoroethylene (PTFE) is inadequate; therefore, the surface should be grafted with biocompatible molecules. Because PTFE is an inert polymer, the adhesion of the biocompatible film may not be appropriate. Therefore, the PFTE surface should be modified to enable better adhesion, preferably by functionalization with amino groups. A two-step process for functionalization of PTFE surface is described. The first step employs inductively coupled hydrogen plasma in the H-mode and the second ammonia plasma. The evolution of functional groups upon treatment with ammonia plasma in different modes is presented. The surface is saturated with nitrogen groups within a second if ammonia plasma is sustained in the H-mode at the pressure of 35 Pa and forward power of 200 W. The nitrogen-rich surface film persists for several seconds, while prolonged treatment causes etching. The etching is suppressed but not eliminated using pulsed ammonia plasma at 35 Pa and 200 W. Ammonia plasma in the E-mode at the same pressure, but forward power of 25 W, causes more gradual functionalization and etching was not observed even at prolonged treatments up to 100 s. Detailed investigation of the XPS spectra enabled revealing the surface kinetics for all three cases.

Hierarchically Inverse Opal Porous Scaffolds from Droplet Microfluidics for Biomimetic 3D Cell Co-Culture

With the advantages of better mimicking the specificity of natural tissues, three-dimensional (3D) cell culture plays a major role in drug development, toxicity testing, and tissue engineering. However, existing scaffolds or microcarriers for 3D cell culture are often limited in size and show suboptimal performance in simulating the vascular complexes of living organisms. Therefore, we present a novel hierarchically inverse opal porous scaffold made via a simple microfluidic approach for promoting 3D cell co-culture techniques. The designed scaffold is constructed using a combined concept involving an emulsion droplet template and inert polymer polymerization. This work demonstrates that the resultant scaffolds ensure a sufficient supply of nutrients during cell culture, so as to achieve large-volume cell culture. In addition, by serially planting different cells in the scaffold, a 3D co-culture system of endothelial-cell-encapsulated hepatocytes can be developed for constructing certain functional tissues. It is also demonstrated that the use of the proposed scaffold for a co-culture system helps hepatocytes to maintain specific in vivo functions. These hierarchically inverse opal scaffolds lay the foundation for 3D cell culture and even the construction of biomimetic tissues.

TADF quenching properties of phenothiazine or phenoxazine-substituted benzanthrones emitting in deep-red/near-infrared region towards oxygen sensing

Aiming to develop new deep-red/near-infrared emitters, benzanthrone as a new acceptor moiety with a rigid molecular structure was used. For the design of target compounds phenothiazine and phenoxazine moieties with strong electron-donating ability were also used. Such combination allowed new materials demonstrating thermally activated delayed fluorescence (TADF) in the long wavelength region to be obtained. The maximum intensity of fluorescence of the solid samples of the synthesized compounds was observed at 700 nm. Electroluminescence was peaked at similar wavelength when the compounds were used as emitters for the fabrication of non-doped organic light-emitting diodes. Due to the different substitutions of benzanthrone moieties, the values of TADF lifetimes at room temperature were found to be of in the range of 291–1198 μs which are directory related to their different oxygen sensing properties. Due to high sensitivity to the presence of oxygen in the atmosphere one of the obtained compounds was used for radiometric oxygen sensing. The film of molecular dispersion of phenoxazine containing compound in inert polymer ZEONEX® showed the ratio of intensity of TADF taken in vacuum and of prompt fluorescence taken under oxygen purge of 15.2. The oxygen sensitivity of the film estimated by Stern-Volmer constant was found to be of 1.6 × 10−4 ppm−1 demonstrating good reversibility. The time dependent density functional theory (DFT) calculations were used for the interpretation of the experimental results related to the structure and photophysical properties of the compounds.