Leibniz-Institut für Polymerforschung Dresden eV

Enhancing both ionic conductivity and mechanical robustness remains a major challenge in designing solid-state electrolytes for lithium batteries. This work presents a novel approach in designing mechanically robust and highly conductive solid-state electrolytes, which involves ionic liquid-based cross-linked polymer networks incorporating polymeric ionic liquids (PILs). First, linear PILs with different side groups were synthesized for optimizing the structure. Molecular weights of the PIL samples, ranging from 30 to 40 kDa, were determined using a complimentary combination of thermal field-flow fractionation (ThFFF) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The aimed for networks were synthesized through the photo-initiated polymerization of a network-forming monomer and a cross-linker, in the presence of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and a PIL bearing quaternized imidazolium groups. The resulting cross-linked membranes - semi-interpenetrating networks - exhibit substantial mechanical strength, with a Young's modulus of 40-50 MPa, surpassing the threshold for solid-state battery separators, while maintaining high ionic conductivity in the range of 4 × 10^-4 S·cm^-1 at 60°C. Notably, the introduction of oligo(ethylene glycol) moieties into the PIL structure significantly enhances ionic conductivity and allows for incorporation of a larger amount of the lithium salt compared to the alkyl-substituted analogs. Moreover, although cross-linking often impairs ionic transport as a result of restricted segmental mobility of the polymer chains, incorporation into the network of highly conductive linear PILs circumvents this issue. This unique combination of properties positions the developed membranes as promising candidates for application in solid-state lithium batteries, effectively addressing the traditional trade-off in electrolyte design.

Owing to fast SARS-CoV-2 mutations, biosensors employing antibodies as biorecognition elements have presented problems with sensitivity and accuracy. To face these challenges, antibodies can be replaced with the human angiotensin converting enzyme 2 (ACE-2), where it has been shown that the affinity between ACE-2 and the receptor binding domain (RBD) increases with the emergence of new variants. Herein, we report on Ni-doped ZnO nanorod electrochemical biosensors employing an ACE-2 peptide (IEEQAKTFLDKFNHEAEDLFYQS-NH₂) as a biorecognition element for detecting Spike (S) Wild-Type (WT) protein. The electrode was fully characterized in terms of electrochemical and physical properties. The sensor showed high cross reactivity with Spike protein B.1.1.7 and Spike protein B.1.351. Still, there was no cross reactivity with the Nucleocapsid protein WT, showing that the biosensor can identify ancestral WT S protein and S protein variants of concern. The device exhibited a LOD of 60.13 ng mL^-1 across an S protein WT concentration range from 200 ng mL^-1 to 1000 ng mL^-1 and a LOQ of 182.22 ng mL^-1. The calculated sensitivity and specificity were 88.88 and 100 %, respectively. These results proved that the Ni-ZnO sensor has promising prospects for SARS-CoV-2 detection and diagnosis of other viruses, employing peptides as biorecognition elements.

Natural rubber (NR) is a biopolymer consisting of cis-1,4-isoprene units extracted from the sap of rubber trees, mainly Hevea Brasiliensis.This rubber is widely used in the automotive and other industries due to its performance and elasticity.However, synthetic rubber has largely replaced natural rubber in many applications because of the poor heat resistance of natural rubber.On the other hand, non-recyclable sulfur-based synthetic rubber composites pose a major environmental issue from the viewpoint of sustainability.In this report, a flexible (non-directional) crosslinking network based on ionic bonds in modified natural rubber (epoxy-modified NR) using dicarboxylic acid and dimethylimidazole (DMI) is presented, which eliminates the disadvantages of natural rubber and outperforms synthetic rubber without compromising its mech. performance.Accelerated aging, temperature scanning stress relaxation, compression set, and temperature-dependent FT-IR analyses confirm the high thermal stability of ionically crosslinked natural elastomer.The ionic crosslinked rubber shows a significant improvement in initial degradation temperature (196 °C) compared to thermally stable synthetic elastomers, such as NBR (acrylonitrile butadiene rubber), CR (polychloroprene rubber), and peroxide-cured EPDM (ethylene propylene diene monomer).Unlike sulfur-cured elastomers, the ionically crosslinked natural rubber exhibits superior cut growth resistance and self-repairing capabilities, as demonstrated by X-ray microtomog.These findings, along with the natural origin of the developed crosslinked elastomers, can reduce environmental damage and the carbon footprint associated with sulfur-cured and petroleum-based synthetic rubber products.