Assessing Polymer-Surface Adhesion with a Polymer Collection

Polymer modification plays an important role in the construction of devices, but the lack of fundamental understanding on polymer-surface adhesion limits the development of miniaturized devices. In this work, a thermoplastic polymer collection was established using the combinatorial laser-induced forward transfer technique as a research platform, to assess the adhesion of polymers to substrates of different wettability. Furthermore, it also revealed the influence of adhesion on dewetting phenomena during the laser transfer and relaxation process, resulting in polymer spots of various morphologies. This gives a general insight into polymer-surface adhesion and connects it with the generation of defined polymer microstructures, which can be a valuable reference for the rational use of polymers

Surface Functionalization of Silicon, HOPG, and Graphite Electrodes: Toward an Artificial Solid Electrolyte Interface

Electrografting of diazonium salts containing a protected alkyne moiety was used for the first functionalization of silicon and highly ordered pyrolytic graphite model surfaces. After deprotection with tetrabutylammonium fluoride, further layers were added by the thiol-yne click chemistry. The composition of each layer was characterized via X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. The same approach was then used to functionalize graphite powder electrodes, which are classically used as negative electrode in lithium-ion batteries. The effect of the coating on the formation of the solid electrolyte layer was investigated electrochemically by cyclovoltammetry and galvanostatic measurements. The modified graphite electrodes showed different reduction peaks in the first cycle, indicating reduced and altered decomposition processes of the components. Most importantly, the electrochemical investigations show a remarkable reduction of irreversible capacity loss of the battery

On the macrocyclization selectivity of meta-substituted diamines and dialdehydes: towards macrocycles with tunable functional peripheries

Abstract: The efficient preparation of functional rigid and soluble macrocycles remains a challenge for synthetic chemists. Here, we exploit the thermodynamic control of dynamic covalent chemistry to investigate the influence of the monomer structure on the macrocyclization selectivity. A series of rigid cyclic hexamer has been synthesized by imine condensation of benzene building blocks, i.e. meta-substituted diamines and dialdehydes, templated by calcium(II) chloride. The monomers were designed to feature various additional functional groups either available for further post-cyclization modifications or acting as solubilizing groups. The cyclization selectivity was systematically investigated and optimized depending on the length of the applied solubilizing group and on the nature of the additional functional group. A selectivity up to 92% was reached for the macrocyclization exhibiting trifluoromethyl and bromine groups at the outer periphery and hydroxyl groups in the cavity. Graphic abstract: [Figure not available: see fulltext.].</p