Changsik Song

In a previous publication, we described the use of biradicals, in that case two TEMPO molecules tethered by an ethylene glycol chain of variable length, as polarizing agents for microwave driven dynamic nuclear polarization (DNP) experiments. The use of biradicals in place of monomeric paramagnetic centers such as TEMPO yields enhancements that are a factor of approximately 4 larger (epsilon approximately 175 at 5 T and 90 K) and concurrently the concentration of the polarizing agent is a factor

Electrically conductive hyaluronic acid (HA) hydrogels incorporated with single-walled carbon nanotubes (CNTs) and/or polypyrrole (PPy) were developed to promote differentiation of human neural stem/progenitor cells (hNSPCs). The CNT and PPy nanocomposites, which do not easily disperse in aqueous phases, dispersed well and were efficiently incorporated into catechol-functionalized HA (HA-CA) hydrogels by the oxidative catechol chemistry used for hydrogel cross-linking. The prepared electroconduc

Abstract Over the past decade, lithium‐ion batteries (LIBs) have been widely applied in consumer electronics and electric vehicles. Polymer electrolytes (PEs) play an essential role in LIBs and have attracted great interest for the development of next‐generation rechargeable batteries with high energy density. Due to the several practical applications of LIBs and high demands for LIBs performance, many state‐of‐the‐art PEs with different structures and functionalities have been developed to regu

Stable pi-dimers are formed upon oxidation of the model units of proposed calix[4]arene-based molecular actuators in a solvent of low dielectric constant (CH 2Cl 2) at room temperature. Evidence from UV-vis, EPR, and DPV are all in agreement with the pi-dimer formation. In addition, pi-dimer formation is dependent upon the conformational flexibility of the calix[4]arene hinge.

Hybrid nanocomposites of N -heterocyclic carbene (NHC)-functionalized conducting polymers (CPs) with gold nanoparticles (AuNPs) were prepared by concurrent disproportionation and oxidative coupling. The formation of hybrid nanocomposites, NHC-CP/AuNPs, in the simultaneous process was confirmed by transmission electron microscopy, powder X-ray diffraction, cyclic voltammetry, and 13 C solid-state NMR analyses. More importantly, the NHC group played a pivotal role in the dispersion of AuNPs. Furth

Herein, we report a facile, one-pot, green, and solvent-less (solid-state) mechanochemical approach toward the synthesis of eco-friendly polyurethanes (PUs) at room temperature using biomass-derived 2,5-bis(hydroxymethyl)furan (BHMF) combined with vibration milling. This approach is simple, straightforward, and very fast even at room temperature because of the instantaneous energy generated during grinding. BHMF, a biomass-derived monomer, was successfully used to synthesize PUs via ball milling

Because of the environmental issues associated with thermoset or network polymers, recyclable polymers are highly in demand, and the use of sustainable biomass-derived ingredients is also becoming increasingly important. In this work, we utilized 2,5-bis(hydroxymethyl)furan as a starting material to produce network polyurethanes (NPUs) under facile, solvent-free (solid-state) ball milling conditions. Urethane bonds may undergo thermally controlled transcarbamoylation, a reversible dynamic covale

Electroconductive hydrogels are composed of 3-dimensionally structured hydrogels and conducting molecules with electrical, optical, and reversible redox properties.

Picket-fence-type substituents effectively suppress the π–π stacking interaction of flat aromatic molecules and enhance solid-state emission for application in organic light-emitting diodes.

The ability to rapidly detect, identify, and monitor chemical warfare agents (CWAs) is imperative for both military and civilian defense. Since most CWAs and their simulants have an organophosphonate group, which is a hydrogen (H)-bond acceptor, many H-bond donors have been developed to effectively bind to the organophosphonate group. Although thioureas have been actively studied as an organocatalyst, they are relatively less investigated in CWA detection. In addition, there is a lack of studies

We report the design and synthesis of annulated thiepins designed to undergo bent-to-planar transformation driven by aromatization under electrochemical control. Thiepins are conjugated seven-membered ring systems with a thioether in the macrocycle. We synthesized thermally stable thiepins that are electropolymerizable to give rise to thiepin-containing electroactive polymers. Extended thiepin systems undergo sulfur extrusion with oxidation, and this feature has utility in peroxide sensing.

We developed a terpyridine-functionalized microgel (<bold>tpy-mG</bold>) for its supramolecular assembly.

Two isomeric polymers, which contain meta - or para -phenylene linkages between conducting segments, have been synthesized and compared by electrochemical methods. The nonconjugated poly(1,5-diacetoxy- m -phenylene tetrathienylene) (PMPT-OAc) showed similar electroactivity to the para -isomer, poly(2,5-diacetoxy- p -phenylene tetrathienylene) (PPPT-OAc), in the cyclic voltammetry and in-situ conductivity measurements. Spectroelectrochemistry showed a similar buildup of sub-band-gap electronic tr