Temperature gradient of vertical air column in gravitational field.

The negative temperature gradient under gravity was observed with a vertical air column inside a practically insulated aluminum cylinder filled with sawdust. The temperature drop rate measured between 90 and 10 cm height positions was as much as 2.22 Km when the diameter of the air column was 60 cm.

Graphene functionalized with poly(vinyl alcohol) as a Pickering stabilizer for suspension polymerization of poly(methyl methacrylate).

Two types of thermally reduced graphenes (TRGs) having different lateral sizes were non-covalently modified with poly(vinyl alcohol) to endow water-dispersibility. The modified TRGs were examined as Pickering stabilizers for the suspension polymerization of methyl methacrylate (MMA). They were effective graphene-based Pickering stabilizers for the system with almost all of the polymerized composite microparticles having a regular spherical shape.

Properties of Graphene/Shape Memory Thermoplastic Polyurethane Composites Actuating by Various Methods.

Shape memory behavior of crystalline shape memory polyurethane (SPU) reinforced with graphene, which utilizes melting temperature as a shape recovery temperature, was examined with various external actuating stimuli such as direct heating, resistive heating, and infrared (IR) heating. Compatibility of graphene with crystalline SPU was adjusted by altering the structure of the hard segment of the SPU, by changing the structure of the graphene, and by changing the preparation method of the graphene/SPU composite. The SPU made of aromatic 4,4'-diphenylmethane diisocyanate (MSPU) exhibited better compatibility with graphene, having an aromatic structure, compared to that made of the aliphatic hexamethylene diisocyanate.

Alumina-coated graphene nanosheet and its composite of acrylic rubber.

A graphene was coated with a thin alumina layer to prepare a novel nanosheet which had high thermal conductivity but low electrical conductivity. The nanosheet with minimal aggregation was prepared effectively by first coating it with aluminum tri-sec-butoxide in anhydrous dimethylformamide, followed by rapid calcination in an inert atmosphere after the hydrolysis of the alkoxide. The morphology observed by scanning electron microscopy and elemental mapping by energy-dispersive X-ray spectrometry showed that the alumina layer coated on the graphene surface was uniform and ultra-thin.

Triazole-containing hydrogels for time-dependent sustained drug release.

The purpose of this study is to develop novel triazole-containing hydrogels (TGs) as drug carrier and to investigate the sustained drug release accomplished by their time-dependent swelling behavior. The synthetic pathway of TGs includes: (1) DCC-coupling on hydroxyethyl methacrylate (HEMA) to prepare HEMA-alkyne (HA), (2) click-coupling to prepare a triazole-ring-containing monomer (TM), and (3) the synthesis of a series of TGs. The aggregation between triazole rings is found to be responsible for drug release controllability.

The effect of oxidation on properties of graphene and its polycaprolactone nanocomposites.

A functionalized graphene sheet (FGS), which was prepared by the thermal reduction of graphite oxide, was modified by oxidation with H2O2. Elemental analysis, X-ray photoelectron spectroscopy, and Fourier transform infrared (FTIR) spectroscopy showed that additional oxygen functional groups, either doubly or singly bound to carbon, were created by the oxidation. The size and electrical conductivity of the FGS were reduced by the oxidation.

Construction of and electrophoretic fluorescence imaging with a nano-porous polyaniline-fluorescein conducting particle system.

Electrophoretic fluorescence images have been fabricated by deposition of nanoporous polyaniline-fluorescein conducting particles onto a micro-patterned polyaniline film.