Annually, about 2.4 million tons of superabsorbent polymers (SAPs) used in disposable diapers are thrown away, polluting our planet. This study aims to explore the potential for reusing SAPs removed from diapers to enhance soil water retention. To this end, the swelling and water retention properties of SAP gels from three different types of diapers were compared to those of an agricultural gel, Aquasorb. Sand was used as a model for soil. When mixed with sand, diaper gels have a swelling degree of ca. 100 g per gram of dried polymer, and a swelling pressure of 12–26 kPa, which are similar to those of Aquasorb gel. Using a synthesized poly(acrylamide-co-sodium acrylate) gel as an example, the correlation between the swelling pressure and the compression modulus of the swollen gel was demonstrated. Soil-hydrological constants were estimated from water retention curves obtained by equilibrium centrifugation of gel/sand mixtures. It was observed that adding 0.3 vol% of diaper gels to sand leads to a 3–4-fold increase in water range available to plants, which is close to that provided by agricultural gel Aquasorb. The water-holding properties were shown to be maintained during several swelling/deswelling cycles in the sand medium. The addition of diaper gels to soil had a significant positive impact on mustard (Brassica juncea L.) seed germination and seedling growth, similar to the agricultural gel Aquasorb. This suggests high potential for the reuse of SAPs from diaper waste to improve soil water retention and water accessibility to plants. This would provide both economic and environmental benefits, conserving energy and raw materials to produce new agricultural gels and limiting the amount of waste.

Polymer-based aqueous redox flow batteries (RFBs) are attracting increasing attention as a promising next-generation energy storage technology due to their potential for low cost and environmental friendliness. The search for new redox-active organic compounds for incorporation into polymer materials is ongoing, with anolyte-type compounds in high demand. In response to this need, we have synthesized and tested a range of new water-soluble redox-active s-tetrazine derivatives, including both low molecular weight compounds and polymers with different architectures. S-tetrazines are some of the smallest organic molecules that can undergo a reversible two-electron reduction in protic media, making them a promising candidate for anolyte applications. We have successfully modified linear polyacrylic acid and poly(N-isopropylacrylamide-co-acrylic acid) microgels with pendent 1,2,4,5-tetrazine groups. Electrochemical testing has shown that the new tetrazine-containing monomers and, importantly, the water-soluble redox polymers, both linear and microgel, demonstrate the chemical reversibility of the reduction process in an aqueous solution containing acetate buffer. This expands the range of water-soluble anodic materials suitable for water-based organic RFBs. The reduction potential value can be adjusted by changing the substituents in the tetrazine core. It is also worth noting that the choice of electrode material plays an important role in the kinetics of the tetrazine reaction: the use of carbon electrodes is particularly beneficial.

In this paper we study in detail the products formed during the process of water-assisted thermal oxidative decomposition (TOD) of polypropylene in the presence of pressurized oxygen. A set of techniques has shown that the main decomposition product in such a process is acetic acid with small amounts of other carboxylic acids (formic, propionic, succinic). The kinetics of carboxylic acid formation is studied by means of gas chromatography-mass-spectrometry as well as capillary electrophoresis, and the possible mechanisms behind the products formation are discussed. The role of water is considered based on the results obtained from substituting H2O with D2O in TOD. Compositions of residual oligomeric fractions as well as gas products are analyzed.

In this paper, we provide a thorough electrochemical study of redox-active nanosized cationic gels which are promising materials for redox flow battery electrolytes. We use two-step synthesis under mild aqueous conditions: precipitation polymerization of nanogels based on poly-(N-isporopylacrylamide-co-N-(3-aminopropyl) methacrylamide hydrochloride) (PNIPAM-co-APMA), and grafting of redox-active 4-(3-carboxypropanamido)TEMPO units to the nanogels. We demonstrate stable reduction-oxidation behavior of such nanogels and suggest a universal approach to evaluate the "effective" concentration and diffusion coefficient of redox-active groups grafted to nanogel particles. For the TEMPO-grafted PNIPAM-co-APMA nanogels we find the "effective" concentration of TEMPO-groups to be approximately 50 % of their total concentration and demonstrate an increase of the "effective" concentration upon electrode rotation. Also, we investigate electron transfer kinetics of redoxactive nanogels and provide an evidence that the adsorbed layer of nanogels facilitates electron transfer.

Here in, we have designed two new unfused non-fullerene small molecules using asymmetric benzo[1,2-b:3.4-b', 6,5-b"]trithiophene (BTT) as the central donor core and different terminal units i. e., 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (NFA-4) and 1,3-diethyl-2-thioxodi hydropyrimidine-4,6 (1H,5H)-dione (NFA-5) and examined their optical and electrochemical properties. Using a wide band-gap copolymer D18, organic solar cells (OSCs) based on bulk heterojunction of D18:NFA-4 and D18:NFA-5 showed overall power conversion efficiency (PCE) of about 17.07 % and 11.27 %, respectively. The increased PCE for the NFA-4-based OSC, compared to NFA-5 counterpart, is due higher value of short circuit current (JSC), open circuit voltage (VOC), and fill factor (FF). Following the addition of small amount of NFA-5 to the binary bulk heterojunction D18:NFA-4, the ternary organic solar cells attained a PCE of 18.05 %, surpassing that of the binary counterparts due to the higher values of which is higher than that for the binary counterparts and attributed to the increased values of JSC, FF, and VOC. The higher value of JSC is linked to the efficient use to excitons transferred from NFA-5 to NFA-4 with a greated dipole moment than NFA-5 and subsequently dissociated into a free charge carrier efficiently.

Bulk radical copolymerisation of N-vinylcaprolactam (VCL) and N-vinylimidazole (VI) is studied experimentally and theoretically. It is shown that the copolymer composition is maintained up to high comonomer conversions. This is explained by a constant ratio of concentrations of comonomers in the reaction zone. The copolymers obtained show thermally induced conformational behaviour. In an aqueous medium above 60 degrees C, they can form compact globular structures with a hydrophobic core of VCL monomer units covered by a hydrophilic corona of VI monomer units, which allows them to be considered as a basis for thermally switchable functional nanostructures.

A new catalytic system based on copper supported on poly(N-vinylimidazole-co-N-vinylcaprolactam) was investigated. Various compositions of copolymers were checked to compare their influence on the catalytic activity. Copolymer with 25 mol% of N-vinylimidazole and 75 mol% of N-vinylcaprolactam showed the best catalytic efficiency along with its recycling ability in the click reaction and Chan-Lam coupling.

Polymer microgels, micrometer-sized cross-linked polymer particles, are considered to be a promising type of advanced materials for a wide range of applications. To enhance the microgels' applicability, it is essential to incorporate various functional groups into a microparticle polymer network. Yet, the availability of functional groups for the interaction with surroundings depends strongly on the properties of the polymer network and has a great impact on further effective usage. In this theoretical study, we address this question and, with the help of coarse-grained molecular dynamics computer simulations, assess the segmental mobility and accessibility of functional groups bound to polymer network depending on microgel architecture and solvent quality. Additionally, we evaluate the minimum number of functional groups needed to facilitate the hopping mechanism between the functional groups (i.e., charge transfer). As an example of practical implementation of the obtained results, we estimate the optimal network topology for redox-active microgels to provide the maximum charge capacity for the dispersion electrolyte in redox-flow batteries.

Interaction of bovine β-lactoglobulin (BLG) with several flavor compounds (FC) (2-methylpyrazine, vanillin, 2-acetylpyridine, 2- and 3-acetylthiophene, methyl isoamyl ketone, heptanone, octanone, and nonanone) was studied by high-sensitivity differential scanning calorimetry. The denaturation temperature, enthalpy, and heat capacity increment were determined at different FC concentrations. It was found that the denaturation temperature and heat capacity increment do not depend on the FC concentration, while the denaturation enthalpy decreases linearly with the FC concentration. These thermodynamic effects disclose the preferential FC binding to the unfolded form of BLG. By the obtained calorimetric data, the free energies of FC binding vs. the FC concentrations were calculated. These dependences were shown to be linear. Their slope relates closely to the overall FC affinity for the unfolded BLG in terms of the Langmuir binding model. The overall BLG affinity for FC varies from 20 M-1 (2-methylpyrazine) up to 360 M-1(nonanone). The maximal stoichiometry of the BLG-FC complexes was roughly estimated as a ratio of the length of the unfolded BLG to the molecular length of FC. Using these estimates, the apparent BLG-FC binding constants were determined. They are in the range of 0.3-8.0 M-1 and correlated strictly with the FC lipophilicity descriptor (logP).

beta-lactoglobulin-oligochitosan (MW 9500 Da) system was studied under conditions of protein-polysaccharide incompatibility, the dipole-charge, and charge-charge protein-polysaccharide interactions at pH 3.0, 5.5, and 6.0, respectively, using ITC, DSC, and DLS. At pH 5.5 and 6.0, the ITC data revealed a complex formation between beta-lactoglobulin and oligochitosan. The binding curves of the protein to the polysaccharide were obtained. The binding parameters, namely, the number of sites (n) and the binding constant (K-b), were estimated in terms of the Langmuir equation. These are n = 2.8 +/- 0.1 and K-b = 10(6.4 +/- 0.1) M-1 at pH 5.5, while n = 1.5 +/- 0.1 and K-b = 10(5.6 +/- 0.1) M-1 at pH 6.0. At pH 3.0, when both the protein and polysaccharide are positively charged, the denaturation parameters of beta-lactoglobulin in the beta-lactoglobulin-oligochitosan system and in the absence of the polysaccharide coincide independently of the system composition. Under conditions of the complexation, the denaturation parameters of beta-lactoglobulin (the denaturation temperature, enthalpy, entropy, and width) displayed complicated dependences on the oligochitosan content. Their analysis supported by measurements of the diffusion coefficients implied that the conformational stability of beta-lactoglobulin in the beta-lactoglobulin-oligochitosan complexes was defined by the complex composition and supramolecular structure of oligochitosan.

The interaction between carboxymethyl cellulose and partially reacetylated chitosan soluble in acidic and alkaline aqueous media is studied by light scattering and isothermal titration calorimetry in a wide pH range. It is shown that the formation of polyelectrolyte complexes (PEC) can occur in the pH range of 6-8, while this pair of polyelectrolytes loses the ability to complexation upon transition to a more alkaline medium. The revealed dependence of the observed enthalpy of interaction on the ionization enthalpy of the buffer indicates the participation of proton transfer from the buffer substance to chitosan and its additional ionization in the binding process. This phenomenon is first observed in a mixture of a weak polybase chitosan and a weak polyacid. The possibility to obtain soluble nonstoichiometric PEC by a direct mixing of the components in a weakly alkaline medium is shown. The resulting PECs are polymolecular particles in shape close to homogeneous spheres with a radius of about 100 nm. The obtained results are promising for creating of biocompatible and biodegradable drug delivery systems.

Two donor–acceptor (D–A) backbone copolymers with different fused ring acceptors, i.e., dithieno [2,3‐e:3′,2′‐g]isoindole‐7,9(8 H)‐dione (DTID) and dithieno[3′,2′:5,6;2″,3″:7,8]naphtho[2,3‐d]imidazol‐9(10 H)‐one (DTNID) and same benzo[1,2‐b:4,5‐b′]dithiophene with alkylated aromatic side as side chains (BDTT) donor, denoted as P133 and P135 are synthesized and used as donor along with narrow bandgap nonfullerene Y6 acceptor for the preparation of polymer solar cells (PSCs). The dielectric constant of P135 :Y6 is higher than that of P133 :Y6 due to the strong electron deficient ability of DTNID compared to DTID, which fostered exciton dissociation and charge transport, constrained charge recombination, and ultimately boosted the power conversion efficiency of P135 :Y6 to 15.11%, which is higher than P133 :Y6 (10.24%). Therefore, these investigations confirm the pronounced potential of fused ring DTNID as an acceptor unit for emerging D–A copolymers for PSCs with high efficiency.

Energetics of chitosan (CS) polyplexes and conformational stability of bound DNA were studied at pH 5.0 by ITC and HS-DSC, respectively. The CS-DNA binding isotherm was well approximated by the McGhee-von Hippel model suggesting the binding mechanism to be a cooperative attachment of interacting CS ligands to the DNA matrix. Melting thermograms of polyplexes revealed the transformation of different conformational forms of bound DNA in dependence on the CS/DNA weight ratio rw. At 0<rw<0.7 two conformational forms were observed and assigned, respectively, to the intact (free) and globular (bound) DNA. A contribution of the globular DNA to the melting enthalpy approached 100 % at the equivalent weight CS content. At higher CS contents a further stabilization of the globular DNA conformation was detected and assigned to the DNA globules in overcharged polyplexes. The polyplex dissociation was studied at pH 7.4 under conditions of zero and a physiological concentration of NaCl. Phase separation of the system was observed in both cases. DNA was almost completely immobilized in the lower phase enriched with CS. At physiological ionic strength, DNA converted from the globular to the intact form although remained to be immobilized in the CS phase.

New small molecule photovoltaic materials containing benzimidazole fragment were prepared by cross-coupling of the corresponding 1-bromo-4-(imidazol-2-yl)benzenes with multiborylated/stannylated polycyclic (het)arenes. Energies of HOMO/LUMO levels were calculated from cyclic voltammetry and UV/VIS spectroscopy data and are within the ranges –5.27... –5.73 and –2.33...–2.89 eV, respectively. Solar cells based on three different perovskites as light absorbing layers and compound SM7 as electron transporting material demonstrated power conversion efficiency values up to 10.78% without doping additives or perovskite engineering.

We have designed a new medium bandgap non-fullerene small-molecule acceptor consisting of an IDT donor core flanked with 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]-thiophene-4-ylidene) malononitrile (TC) acceptor terminal groups (IDT-TC) and compared its optical and electrochemical properties with the IDT-IC acceptor. IDT-TC showed an absorption profile from 300 to 760 nm, and it has an optical bandgap of 1.65 eV and HOMO and LUMO energy levels of -5.55 and -3.83 eV, respectively. In contrast to IDT-IC, IDT-TC has an upshifted LUMO energy level, which is advantageous for achieving high open-circuit voltage. Moreover, IDT-TC showed higher crystallinity and high electron mobility than IDT-IC. Using a wide bandgap D-A copolymer P as the donor, we compared the photovoltaic performance of IDT-TC, IDT-IC, and IDT-IC-Cl nonfullerene acceptors (NFAs). Polymer solar cells (PSCs) using P: IDT-TC, P: IDT-IC, and P:IDT-IC-Cl active layers achieved a power conversion efficiency (PCE) of 14.26, 11.56, and 13.34%, respectively. As the absorption profiles of IDT-IC-Cl and IDT-TC are complementary to each other, we have incorporated IDT-TC as the guest acceptor in the P: IDT-IC-Cl active layer to fabricate the ternary (P:IDT-TC: IDT-IC-Cl) PSC, demonstrating a PCE of 16.44%, which is significantly higher than that of the binary BHJ devices. The improvement in PCE for ternary PSCs is attributed to the efficient exploitation of excitons via energy transfer from IDT-TC to IDT-IC-Cl, suitable nanoscale phase separation, compact stacking distance, and more evenly distributed charge transport.

A new acceptor unit anthra[1,2-b: 4,3-b': 6,7-c'']trithiophene-8,12-dione (А3Т) (A2) is synthesized and used to design D-A1 -D-A2 medium bandgap donor copolymers with same thiophene (D) and A2 units but different A1, i.e., fluorinated benzothiadiazole (F-BTz) and benzothiadiazole (BTz) denoted as P130 and P131, respectively. Their detailed optical and electrochemical properties are examined. The copolymers show good solubility in common organic solvents, broad absorption in the visible spectral region from 300 to 700 nm, and deeper HOMO levels of -5.45 and -5.34 eV for P130 and P131, respectively. Finally, an optimized polymer solar cell (PSC) based on P131 as the donor and narrow bandgap non-fullerene small molecule acceptor Y6 demonstrated a power conversion efficiency (PCE) of >11.13%. To further improve the efficiency of the non-fullerene PSC, the P130 is optimized by introducing a fluorine atom into the BTz unit, F-BTz acceptor unit, and PCE PSC based on P130: Y6 active layer increased to >15.28%, which is higher than that for the non-fluorinated analog P131:Y6. The increase in the PCE for former PSC is attributed to the more crystalline nature and compact π-π stacking distance, leading to more balanced charge transport and reduced charge recombination. These remarkable results demonstrate that A3T-based copolymer P130 with F-BTz as the second acceptor is a promising donor material for high-performance PSCs.

A novel graded-HOMO-level hole transport polymer (g-HTP) is proposed for the first time with spiro-polyfluorene (sPF) as the main chain and the three hole-transporting moieties triphenyl amine (TPA), carbazole (Cz), and N,N '-dicarbazolyl-3,5-benzene (mCP) as side chains for effective hole injection across the large barrier 1.4 eV into the green-emission core-shell quantum dot (QD) CdSe/ZnS emission layer in inverted QD light-emitting diode (i-QLED): ITO/ZnO/QD/HTP/MoO3/Al, in which both oleophilic ligands (OA and TOP) in the QD are partially removed from QD surface by annealing at 270 degrees C for preventing dissolution by solvent in subsequent coating of hole transport material (HTM) solutions atop and also improving electron and hole mobilities, especially the former. The proposed g-HTP with various m:n mole ratios of mCP to TPA/Cz moieties along with various reported HTMs (PVK, Poly-TPD and TFB) are investigated. Among them, the proposed g-HTP with the comonomer mole ratio 1:1 gives the best performance eta(max) 36.1 cd A(-1) and B-max 208 600 cd m(-2), which is the highest performance among the reported i-QLEDs with single hole-transport layer ever documented. In addition, its efficiency roll off is low from 35.8 cd A(-1) at 10 000 cd m(-2) to 31.1 cd A(-1) at 100 000 cd m(-2).

The virucidal activity of a series of cationic surfactants differing in the length and number of hydrophobic tails (at the same hydrophilic head) and the structure of the hydrophilic head (at the same length of the hydrophobic n-alkyl tail) was compared. It was shown that an increase in the length and number of hydrophobic tails, as well as the presence of a benzene ring in the surfactant molecule, enhance the virucidal activity of the surfactant against SARS-CoV-2. This may be due to the more pronounced ability of such surfactants to penetrate and destroy the phospholipid membrane of the virus. Among the cationic surfactants studied, didodecyldimethylammonium bromide was shown to be the most efficient as a disinfectant, its 50% effective concentration (EC50) being equal to 0.016 mM. Two surfactants (didodecyldimethylammonium bromide and benzalkonium chloride) can deactivate SARS-CoV-2 in as little as 5 s.

Polymer materials are designed for a limited service life; therefore, the problem of minimizing polymer waste, as well as their subsequent disposal, is becoming increasingly urgent. Polymer waste can be minimized either through secondary processing (which requires separate collection and sorting) or through the development of waste-free closed-cycle technologies. The final disposal of a polymer material occurs when it is buried in the soil in a landfill or when incinerated in an incineration plant. The main scientific problems associated with the optimal planning of all stages of the life cycle of a polymer material-its production, operation, and disposal-are discussed.

In this work, the interaction between the negatively charged surfactant sodium dodecyl sulfate (SDS) and partially N-reacetylated chitosan (RA-CHI), which is soluble at pH range up to pH 12, is studied in a wide pH range including alkaline media by light scattering (LS) and isothermic titration calorimetry (ITC). It is shown that in the weakly alkaline medium (pH 7.4), RA-CHI/SDS interaction is exothermic and cooperative. This interaction is found to be coupled with proton transfer from the buffer substance to chitosan as it is revealed by the dependence of the measured heat release on the ionization enthalpy of the buffer. At higher pH values (pH > 8), another mechanism of interaction is observed that include SDS micellization induced by hydrophobic interactions with polymer segments, so that no phase separation occurred in these mixtures. The results obtained can contribute to expand the knowledge about application of chitosan for preparation of pharmaceutical and cosmetic compositions containing anionic surfactants.