Materials for polymer electronics applications – semiconducting polymer thin films and nanoparticles

The paper presents two different approaches to nanostructured semiconducting polymer materials: (i) the generation of aqueous semiconducting polymer dispersions (semiconducting polymer nanospheres SPNs) and their processing into dense films and layers, and (ii) the synthesis of novel semiconducting polyfluorene-block-polyaniline (PF-b-PANI) block copolymers composed of conjugated blocks of different redox potentials which form nanosized morphologies in the solid state.     

Preparation of biodegradable and thermoresponsive enzyme–polymer conjugates with controllable bioactivity via RAFT polymerization

The preparation of biodegradable and thermoresponsive enzyme–polymer bioconjugates with controllable enzymatic activity via reversible addition−fragmentation chain transfer (RAFT) polymerization and amidation conjugation reaction is presented. A new 2-mercaptothiazoline ester functionalized RAFT agent with intra-disulfide linkage was synthesized and used as chain transfer agent (CTA) to generate a biocompatible homopolymer, poly(ethyleneglycol) acrylate (polyPEG-A) and a thermoresponsive copolymer of poly(ethyleneglycol) acrylate with di(ethyleneglycol)ethyl ether acrylate [poly(PEG-A-co-DEG-A)]. These biodegradable and thermoresponsive polymers were then conjugated to the surface of glucose oxidase (GOx) under mild condition to afford the biodegradable and thermoresponsive enzyme–polymer conjugates. Cleavage of the polymer chains from the GOx surface obviously recovered the enzymatic activity. The thermoresponsive test of GOx-poly(PEG-A-co-DEG-A) revealed that the bioconjugate exhibited regular enzymatic activity fluctuation upon the temperature change below or above the lower critical solution temperature (LCST). The as-prepared enzyme–polymer conjugates were also characterized using ¹H NMR, UV–vis spectroscopy, polyacrylamide gel electrophoresis (PAGE) and biocatalytic activity tests. These smart enzyme–polymer conjugates would envision promising applications in biotechnology and biomedicine.     

Synthesis and characterization of biodegradable polymer： Poly （ethene maleic acid ester-co-D,L-lactide acid）

A novel biodegradable polymer--poly （ethene maleic acid ester-co-D,L-lactide acid） was synthesized by copolymerizing lactide and prepolymer, which was prepared by the condensation of maleic anhydride and glycol, using p-toluene sulphonic acid as a catalyst, attempting to improve the hydrophilicity, increase flexibility and modulate the degradation rate. FTIR,^1H NMR, MALLS and DSC were employed to characterize these polymers.     

Biomarkers for Alzheimer's Disease – An Overview

Alzheimer's disease (AD) is a complex neurodegenerative disorder with a significant global impact on public health. The emergence of atypical clinical phenotypes challenges traditional diagnostic approaches, necessitating a deeper exploration of biomarkers for accurate identification. The US Food and Drug Administration (FDA) classification of biomarkers and their integration into different stages of AD provide a structured framework for their application in research and clinical settings. Within the context of AD drug development, biomarkers are essential for participant selection, target engagement evaluation, and assessment of pathological hallmarks, including Aβ and tau protein abnormalities. The incorporation of nanoparticles with a biodegradable approach introduces innovative strategies to address the complexities of AD. This paper extensively discusses biomarkers associated with synaptic dysfunction, neuroinflammation, and glial activation, recognizing their significance in elucidating disease mechanisms. Common pathologies such as synuclein and TDP-43 further underscore the multifaceted nature of AD. Current biomarkers for AD diagnosis, encompassing cerebral spinal fluid (CSF) biomarkers and various imaging modalities, reflect the ongoing efforts to enhance early detection and monitoring. Intriguingly, novel biomarkers continue to emerge, offering promising avenues for improved understanding and intervention. Current review provides a comprehensive survey of biomarkers for AD, elucidating their diverse roles across different aspects of the disease. By highlighting their contributions to diagnosis, drug development, and mechanistic insights, this overview underscores the importance of biomarker research in the pursuit of effective AD management and treatment strategies.     

Photocatalysis of β-blockers – An overview

Photocatalysis is one of the most effective advanced oxidation processes to remove residual pharmaceuticals from the aquatic environment. β-Blockers are the group of pharmaceuticals commonly found in the environment and are showing potential risk to the aquatic and terrestrial organisms. This paper provides an overview of different photocatalytic procedures found in the literature for the abatement of β-blockers.     

Nanotubes as polymer composite reinforcing additive materials – A comparative study

Nitrogen-doped bamboo-shaped carbon nanotubes (N-BCNTs) and their non-doped conventional counterparts, multiwalled carbon nanotubes (MWCNTs) were compared as polymer reinforcing additives in polyvinyl chloride (PVC) matrix. The nanotubes were synthetized by catalytic chemical vapor deposition (CCVD) method. The purity of both nanotubes was measured by thermogravimetric analysis (TGA) and found to be >91%. Further analysis on the morphology and size of the carbon nanotubes (CNTs) were performed by transmission electron microscopy (TEM). The PVC powder was impregnated with CNTs in ethanol by using tip ultrasonicator. The dispersion media was evaporated, and the CNT/PVC powder was used to produce polymer fibers. The orientation of carbon nanotubes in the PVC matrix was characterized by scanning electron microscopy (SEM), and the presence of nanotubes were confirmed in case of all PVC samples. It can be observed on the SEM images that the nanotubes are fully covered with PVC. The tensile strength of the nanotube containing samples was tested and the N-BCNT/PVC composite was found to be better in this sense, thanks to the extraordinary structure of the nanotube. In case of the N-BCNT/PVC composite the measured young modulus was 39.7% higher, while the elongation at brake decreased by 33.6% compare to the MWCNT/PVC composite. These significant differences in the mechanical properties of the composites can be explained with the stronger interaction between N-BCNTs and PVC.     

Polymerization with Fischer-Tropsch olefins – a new challenge in polymer science

Co- and ter-polymerization of ethylene with Fischer-Tropsch derived olefins having odd carbon number and branched olefins are investigated. A method of preparation of a robust, high productivity Ziegler-Natta catalyst suitable for ethylene co-polymerization with Fischer Tropsch olefin is reviewed. In supporting titanium tetrachloride, an attempt was made to control the titanium oxidation state. The resulting experimental data were fitted to a sub-sites model that associates titanium oxidation state with catalyst activity.     

Gel permeation chromatography – Atmospheric pressure chemical ionization – Mass spectrometry for characterization of polymer additives

The study presents the possibility to use gel permeation chromatography (GPC) with atmospheric pressure chemical ionization (APCI)-mass spectrometry for the analysis of polymer additives having molecular weights up to 2,000?g?mol^?1. Irganox 1010, Irganox 1035, Irganox 1076, and Irganox 3114 were analyzed in chloroform using 2.1-mm-internal-diameter GPC columns at the optimum flow rate of 50?µL min^?1. Based on the chemical formula, the APCI interface combined with chlorine ionization enabled us to predict the expected mass spectrum and to build libraries without needing to inject each additive separately. Quantification limits of about 100?µg of additive in 1?g of polymer (100?ppm) can be reached using single-ion-monitoring methods based on the calculated isotope distribution.     

An alternative route to dye–polymer complexation study using asymmetrical flow field-flow fractionation

The goal of the present work is to apply the versatile asymmetrical flow field-flow fractionation (AF4) coupled to UV and light scattering detection for the characterization of hyperbranched poly(ethylene imine) decorated with maltose shell (PEI-Mal) and the polar dye Rose Bengal (RB) in respect to their complexation behaviour. The quantitative determination of the non-complexed dye was carried out using the ultra-filtration effect of AF4 during the focussing phase, whereas the non-bound RB is filtrated and transported out of the channel while the complex of RB and PEI-Mal remains inside. A calibration with UV detector (550 nm) was established and different parameters (e.g. membrane material, molecular weight cut-off and stability of both, pure RB and RB@PEI-Mal complexes in solution) were investigated and verified. Successful reproducibility tests were performed. First complexation studies with the developed method were applied successfully with different mixture compositions of RB and PEI-Mal.     

Organotin–oxotungstate coordination polymer: An efficient catalyst for the selective oxidation of amines

The organometallic coordination polymer [(nBu₃Sn)₂WO₄] catalyzed the selective oxidation of secondary and primary amines to nitrones and oximes, respectively. The catalyst was found to be reusable for five catalytic cycles without any appreciable loss in activity. Under the optimized reaction conditions [4 mol% catalyst, 3–4 equiv of hydrogen peroxide (30 wt%, aqueous solution), methanol as the solvent, r.t.], the corresponding nitrones and oximes were obtained with good efficiency.     

Welding dynamics in an atomistic model of an amorphous polymer blend with polymer–polymer interface

We consider an atomistic model of thermal welding at the polymer-polymer interface of a polyetherimide/polycarbonate blend, motivated by applications to 3D manufacturing in space. We follow diffusion of semiflexible chains at the interface and analyze strengthening of the samples as a function of the welding time t_w by simulating the strain–stress and shear viscosity curves. The time scales for initial wetting, and for fast and slow diffusion, are revealed. It is shown that each component of the polymer blend has its own characteristic time of slow diffusion at the interface. Analysis of strain–stress demonstrates saturation of the Young's modulus at t_w = 240 ns, while the tensile strength continues to increase. The shear viscosity is found to have a very weak dependence on the welding time for t_w > 60 ns. It is shown that both strain–stress and shear viscosity curves agree with experimental data.     

Alternative and Uncommon Acylating Agents – An Alive and Kicking Methodology

Functionalizing and derivatising organic molecules is a centerpiece in organic synthesis. Succinctly manipulating and installing acyl moieties in organic molecules spurred the interest of chemists owing to its occurrence in natural products, bioactive molecules, pharmaceuticals, and advanced materials. Traditionally, access to acylation reaction was achieved by Friedel-Crafts reaction, Schotten-Baumann, and Vilsmeier-Haack acylation, however, these protocols own pitfalls. Further to make the acylation process attractive and environmentally friendly, toluene, aldehydes, alcohols, α-keto acids, amines, amides, esters, ethers, nitriles, alkynes, alkenes, ketenes, N-acylbenzotriazoles, ketones, thioacids, oximes, thiazolium carbinols, PIDA, diacyl disulfides and acyl salts were used as an acyl surrogates/reagents. Amusingly, these acylating reagents are considered uncommon and alternative to carboxylic acids, acid chlorides and acetic anhydrides. This short review aims to encompass the usage of acylating agents in transition-metal, metal-free, light-driven and other demanding conditions, and thus reveals their practicality.     

SrIrIn6 – An Intergrowth of SrIrIn4 with Indium Slabs

The indium-rich intermetallic compound SrIrIn₆ was synthesized from the elements in a sealed tantalum ampoule at 1173 K, followed by slow cooling for crystal growth. SrIrIn₆ crystallizes with a new structure type which was characterized by X-ray powder and single crystal diffraction: Pmma, a = 852.34(2), b = 434.54(5), c = 1059.18(6) pm, wR₂ = 0.0178, 884 F² values, and 32 variables. The SrIrIn₆ structure shows two basic building units: (i) Ir@In₉ tricapped trigonal prisms (261–292 pm Ir–In) and (ii) distorted bcc In@In₈ cubes (301 to 329 pm In–In). The strontium cations fill cages within the complex three-dimensional [IrIn₆] network and have coordination number 13 (Sr@In₁₃) in form of a tricapped pentagonal prism. The SrIrIn₆ structure can be described as a simple intergrowth variant of SrIrIn₄ (LaCoAl₄ type) with indium slabs. The crystal chemical similarities with the structures of SrIrIn₄, SrIr₂In₈ and Eu₃Ir₂In₁₅ are discussed.     

Merocyanine ↔ spiropyran transformation in a polymer matrix: An example of a dispersive chemical reaction

The non-exponential time dependence of spiropyran ↔ merocyanine transformation in a co-polymer has been reinvestigated experimentally and analysed in terms of a dispersive first-order chemical reaction. Non-exponential dependence can be accounted for by a Gaussian distribution of activation energies whose width decreases with increasing temperature.     

Recent developments in sol-gel based polymer electrolyte membranes for vanadium redox flow batteries – A review

The current importance of energy production from renewable sources stimulated interest in energy storage systems. Recent research has focused on developing vanadium redox flow batteries (VRFB) for large scale energy storage owing to their cost-effectiveness, flexible design, energy efficiency and long cycle life. Nafion the preferred membrane in VRFB systems has an overall cost of more than 11% in these systems. However, due to its drawbacks of high permeability and high cost limit its suitability for commercial use. Many researchers are therefore keen to develop new chemical designs for synthetic membranes, such as perfluorinated, partially fluorinated, hydrocarbon based and organic-inorganic composite membrane. The sol-gel process, which is mainly based on hydrolysis and condensation reaction offers the possibility of homogeneous preparation of membranes, leading to high proton conductivity and reduced vanadium ion permeability, thereby greatly increasing the cell efficiency. This review summarizes recent development in the synthesis and applications of sol-gel based proton exchange membranes for VRFB system, on which many researchers have been working in recent years. We also discuss critical research areas and the future development of cost-effective sol-gel based membranes for attractive energy storage systems.     

Mixed conducting polymers on ion-conducting sensor glasses – charge transfer in the system polymer/glass

Mixed ion/electron conducting polymer layers based on polypyrrole have been used as internal reference electrodes in all-solid-state pH glass electrodes. The effect of the nature and composition of the polymer used and of the deposition technique applied on the performance of the resulting sensor has been studied. For this purpose, crucial sensor properties, e.g. parameters of the calibration function, response behaviour and complex impedance, have been determined experimentally at room temperature. The results show that several properties studied remained nearly uninfluenced by changes of the polymer composition. The zero potential point of the calibration line was found to be the most sensitive parameter. Principally, almost all mixed conducting polymers used seems to result in a stable charge transfer in the system polymer/glass.     

Novel polymer system for molecular imprinting polymer against amino acid derivatives

Molecular imprinting polymers (MIPs) against N-Cbz-L-Tyr were prepared utilizing different polymer systems and evaluated in HPLC mode. It was found that MEP utilizing cocktail functional monomers, acrylamide 2-vinylpyridine showed better molecular recognition and better separation ability for the template molecule than those utilizing other functional monomers. MIP utilizing trimethylolpropane trimethacrylate as cross-linker showed higher load capacity and separation factor than those utilizing ethylene glycol dimethacrylate as cross-linker. Increasing the concentration of competing solvent, acetic acid weakened the ionic interaction and hydrogen bonding between the analyte and the functional monomers, 2-vinylpyridine and acrylamide, when the template enantiomer was separated by HPLC. Therefore increasing of the concentration of acetic acid leads to decreasing of capacity factor, separation factor and resolution.     

Shorter alkyl chain in thieno[3,4-c]pyrrole-4,6-dione(TPD)-based large bandgap polymer donors – Yield efficient non-fullerene polymer solar cells

Typically,conjugated polymers are composed of conjugated backbones and alkyl side chains.In this contribution,a cost-effective strategy of tailoring the length of alkyl side chain is utilized to design highperforming thieno[3,4-c]pyrrole-4,6-dione(TPD)-based large bandgap polymer donors PBDT-BiTPD(Cχ)(χ=48,52,56),in which x represents the alkyl side chain length in term of the total carbon number.A combination of light absorption,device,and morphology examinations make clear that the shorter alkyl side chains yield(i) higher crystallinity and more predominant face-on crystallite orientation in their neat and BHJ blend films,(ii) higher charge mobilities(6.7×10^-4 cm~2 V^-1 s^-1 for C48 vs.3.2×10^-4 cm~2 V^-1 s^-1 for C56),and negligible charge recombination,consequently,(iii) significantly improved fill-factor(FF) and short current(J_SC),while almost the same open circuit voltage(V_OC) of ca.0.82 V in their corresponding BHJ devices.In parallel,as alkyl side chain lengths decrease from C56 to C48,power conversion efficiencies(PCEs) increased from 7.8% for C56 to 11.1% for C52,and further to14.1% for C48 in their BHJ solar cells made with a narrow bandgap non-fullerene acceptor Y6.This systematic study declares that shortening the side chain,if providing appropriate solubility in device solution processing solvents,is of essential significance for developing high-performing polymer donors and further improving device photovoltaic performance.