Liquid-Repellent Films Comprising Octamethylsilsesquioxane Selected Based on Three-Dimensional Solubility Parameters.

On the basis of Hansen solubility parameters (HSP), we investigated octamethylsilsesquioxane (OMS), a siloxane compound with a cage-like structure and methyl side chains, as an omniphobic substance. The HSP of OMS were determined through dissolution tests to be similar to those of polytetrafluoroethylene (PTFE), leading to the prediction that films comprising OMS should possess liquid-repellency comparable to films comprising PTFE. Indeed, an electroless-plated Ni-P film composite with OMS particles (Ni-P/OMS film) exhibited liquid-repellency comparable to or higher than that of the Ni-P film composite with PTFE particles, except toward 1-bromonaphthalene, which has a low surface free energy. Moreover, the hydrophilic influence of the Ni-P matrix was eliminated by the use of polydimethylsiloxane (PDMS) as the matrix instead of Ni-P, resulting in enhanced liquid-repellency and water-sliding behavior of the solution-sprayed PDMS film composite with the OMS particles (PDMS/OMS film). These films comprising OMS particles are promising candidates for nonfluorinated liquid-repellent films.

Nontoxic organic solvents identified using an a priori approach with Hansen solubility parameters.

Nontoxicities of organic solvents were predicted using Hansen solubility parameters and various truly nontoxic solvents were identified according to the prediction. The nontoxicity of solvents originates from their exhibition of poor solubility or low diffusivity toward cell constituents and good stability against hydrolytic degradation.

Efficient Catalytic Electrode for CO2 Reduction Realized by Physisorbing Ni(cyclam) Molecules with Hydrophobicity Based on Hansen's Theory.

An electrochemical electrode physisorbed with Ni(cyclam) complex molecules containing tetraphenylborate ions (BPh4(-)) as counteranions shows catalytic activity for the reduction reaction of CO2 to CO in an aqueous electrolyte, superior to that of an electrode physisorbed with conventional [Ni(cyclam)]Cl2 complex molecules. The BPh4(-)-containing Ni(cyclam) is inferred as having high hydrophobicity based on its Hansen solubility parameter (HSP), with an interaction sphere excluding HSPs of water in a three-dimensional vector space. The high hydrophobicity of BPh4(-)-containing Ni(cyclam) molecules inhibits their dissolution into aqueous electrolyte and retains their immobilization onto the electrode surface, which we believe to result in the improved catalytic activity of the electrode physisorbed with them. HSP analysis also provides an optimized mixing ratio of solvents dissolving BPh4(-)-containing Ni(cyclam) molecules.

Optically tunable amino-functionalized graphene quantum dots.

Amino-functionalized graphene quantum dots (af-GQDs) with discrete molecular weights and specific edges were self-limitedly extracted from oxidized graphene sheet. Their optical properties can be precisely controlled only by the selective and quantitative functionalization at the edge sites. The af-GQDS exhibit bright colorful fluorescence under a single-wavelength excitation.

Alignment-retainable nitrogenation of cylindrical carbon nanotubes by thermal reaction with ammonia following UV oxidation: chemical alteration effects on electrical conductivity.

Cylindrical carbon nanotubes (CNTs) pretreated by UV irradiation were able to react with NH(3) to give nitrogen-containing CNTs without destroying their vertically aligned morphology. This process provided incorporation of nitrogen mostly at pyridinic and pyrrolic sites and promoted disordering, which was correlated with decreased electrical conductivity of CNT yarns.

Anti-agglomerating effect in vertically aligned carbon nanotubes derived by antisolvent precipitation of naphthalene.

We developed a novel anti-agglomeration method that enables preservation of the vertical alignment of carbon nanotubes (CNTs) during desiccation of wet CNTs by utilizing antisolvent precipitation and sublimation of naphthalene (Nap). Moreover, we succeeded in depositing Pt nanoparticles onto CNTs without collapse of the vertically aligned morphology by this method.