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End date: 2020 × Start date: 2020 × Has files: Yes × Version: publishedVersion × Publisher: Cambridge : RSC Publ. × WGL Institute: IPF ×

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Now showing 1 - 3 of 3
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    Beyond graphene oxide: Laser engineering functionalized graphene for flexible electronics
    (Cambridge : RSC Publ., 2020) Rodriguez, Raul D.; Khalelov, Alimzhan; Postnikov, Pavel S.; Lipovka, Anna; Dorozhko, Elena; Amin, Ihsan; Murastov, Gennadiy V.; Chen, Jin-Ju; Sheng, Wenbo; Trusova, Marina E.; Chehimi, Mohamed M.; Sheremet, Evgeniya
    Carbon nanomaterials, especially graphene, are promising due to their abundance and the possibility to exploit them in lightweight, flexible, and wearable electronics enabling paradigms such as the Internet of Things. However, conventional methods to synthesize and integrate graphene into functional materials and flexible devices are either hazardous, time demanding, or excessively energy-consuming. To overcome these issues, here we propose a new concept based on the laser processing of single-layer diazonium-functionalized graphene. This is a safe, inexpensive, and environmentally-friendly method making it a competitive alternative for graphene-device fabrication. Flexible chemiresistors exhibit sensitivity for breath (water vapor and CO2) and ethanol detection up to 1500% higher than laser-reduced graphene oxide devices. We attribute this enhanced sensitivity to an optimal balance between structural defects and electrical conductivity. Flexible electronic circuits demonstrate a superb resilience against scratching and high current stability up to 98% with durability against 180° bending cycles for continuous operation of several weeks. This work can impact biomedical technology and electronics where tunable electrical conductivity, sensitivity, and mechanical stability are of uttermost importance. © 2020 The Royal Society of Chemistry.
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    Synthesis and complex self-assembly of amphiphilic block copolymers with a branched hydrophobic poly(2-oxazoline) into multicompartment micelles, pseudo-vesicles and yolk/shell nanoparticles
    (Cambridge : RSC Publ., 2020) Daubian, Davy; Gaitzsch, Jens; Meier, Wolfgang
    We report on the synthesis and self-assembly of poly(ethylene oxide)-block-poly(2-(3-ethylheptyl)-2-oxazoline) (PEO-b-PEHOx), a new amphiphilic diblock copolymer obtained via microwave-assisted polymerization of EHOx using a new nosylated PEO macroinitiator. The kinetics of the polymerization in different solvents was crucial to optimize the synthesis and revealed a controlled, yet fast polymerization of the AB diblock copolymer. Differential scanning calorimetry proved that PEO-b-PEHOx shows glass transition temperatures below room temperature, making it suitable for a wide range of self-assembly methods, especially under mild and solvent-free conditions. Self-assembly of PEO-b-PEHOx was then performed using film rehydration and solvent switch. In both cases, we were able to show the formation of various complex structures (multi-compartment micelles (MCMs), pseudo-vesicles and yolk/shell nanoparticles) by light scattering, TEM and Cryo-TEM. Our results show that PEO-b-PEHOx is a potent new AB diblock copolymer due to its fast synthesis and unique self-assembly behavior.
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    STM induced manipulation of azulene-based molecules and nanostructures: the role of the dipole moment
    (Cambridge : RSC Publ., 2020) Kühne, Tim; Au-Yeung, Kwan Ho; Eisenhut, Frank; Aiboudi, Oumaima; Ryndyk, Dmitry A.; Cuniberti, Gianaurelio; Lissel, Franziska; Moresco, Francesca
    Among the different mechanisms that can be used to drive a molecule on a surface by the tip of a scanning tunneling microscope at low temperature, we used voltage pulses to move azulene-based single molecules and nanostructures on Au(111). Upon evaporation, the molecules partially cleave and form metallo-organic dimers while single molecules are very scarce, as confirmed by simulations. By applying voltage pulses to the different structures under similar conditions, we observe that only one type of dimer can be controllably driven on the surface, which has the lowest dipole moment of all investigated structures. Experiments under different bias and tip height conditions reveal that the electric field is the main driving force of the directed motion. We discuss the different observed structures and their movement properties with respect to their dipole moment and charge distribution on the surface.