Digital Commons Network^™

Confinement-Induced Ordering Of Alkanes Between An Elastomer And A Solid Surface, Ali Dhinojwala

Ali Dhinojwala

We have studied the molecular structure of liquid alkanes confined between a flexible elastomeric poly(dimethyl siloxane) lens and a rigid sapphire substrate using surface-sensitive infrared-visible sum frequency generation spectroscopy. The reduction in the gauche defects suggests ordering of liquid alkanes under confinement. The cooling of confined liquid below the freezing temperature leads to crystallization with alkane molecules lying on the substrate with the symmetry axis parallel to the surface normal. This structure is very different from the bulk alkane crystals next to sapphire or air interfaces.

Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

White Light Electrophosphorescence From Polyfluorene-Based Light-Emitting Diodes:€‰ Utilization Of Fluorenone Defects†, Xiong Gong

Xiong Gong

Poly(9,9-dioctylfluorene-co-fluorenone) with 1% fluorenone, (PFO−F(1%)), was synthesized as a model compound to investigate the optical and electrical effects of fluorenone defects in poly(9,9-dioctylfluoren-2,7-diyl), PFO. Photoluminescence (PL) and electroluminescence (EL) measurements demonstrate that PFO−F(1%) emits stable green light. PL and EL studies indicate that Förster energy transfer to and charge carrier trapping on fluorenone defects (with subsequent fluorenone emission) are responsible for the color degradation typically observed with the polyfluorenes. By utilization of “fluorenone defects” in PFO−fluorenone copolymers (PFO−F), white electrophosphorescent light-emitting diodes were fabricated. Polymer blends were spin-cast from solution containing PFO, PFO−F (1%), and tris[2,5-bis(9,9-dihexylfluoren-2-yl)pyridine-κ2NC3]iridium(III), Ir(HFP)3. The white emission …

Growth Dynamics Of Isotactic Polypropylene Single Crystals During Isothermal Crystallization From A Miscible Polymeric Solvent, Thein Kyu

Thein Kyu

The present article presents a spatiotemporal growth of isotactic polypropylene (iPP) single crystals, melt crystallized from a polymeric solvent, i.e., poly (ethylene octene) copolymer that is known to be miscible with iPP. Optical and atomic force microscopic investigations reveal that the melt grown single crystals of iPP develop in the form of two parallel rows of crystal lamellae, but these crystals merge at the tips. To elucidate the mechanism of these emerging parallel rows of iPP crystals, a phase field model pertaining to solidification phenomena has been employed that involves a nonconserved crystal order parameter and a chain-tilting angle. This …

Does Active Learning Work? A Review Of The Research, Michael Prince

Michael J. Prince

No abstract provided.

Stabilized Blue Emission From Polyfluorene-Based Light-Emitting Diodes: Elimination Of Fluorenone Defects, Xiong Gong

Xiong Gong

This work was partially supported by the Mitsubishi Chemical Center for Advanced Materials at UCSB and the Air Force Office of Scientific Research through the MURI Center (“Polymeric Smart Skins”), Charles Lee, Program Officer. Synthesis of the CF3OXD and related tetrahedrally coordinated molecules was supported by a grant to G. Bazan from DuPont Displays. The XPS results were obtained by using the MRL (Material Research Laboratory at UCSB) Central Facilities supported by the National Science Foundation under DMR 96-32716. We thank Prof. W. R. Salaneck of Linköping University (Sweden) for important comments. X. Gong is grateful to Dr. Gang Yu …

High-Efficiency Polymer-Based Electrophosphorescent Devices, Xiong Gong

Xiong Gong

High efficiency electrophosphorescence has been achieved by using [Ir(DPF)3]-doped polyvinylcarbazole/biphenyl-1,3,4-oxadiazole co-polymers (see Figure). Light-emitting devices with luminous efficiencies up to 36 cd/A can be realized with polymeric host/heavy metal complex guest systems, fabricated by processing the luminescent layer from solution.

Bioremediation Of Oil Refinery Wastes, Michael Prince, Y. Sambasivam

Michael J. Prince

No abstract provided.

Transition Electrolyte Concentration For Bubble Coalescence, Michael Prince, H. Blanch

Michael J. Prince

No abstract provided.

Bubble Coalescence And Break-Up In Air Sparged Biochemical Reactors, Michael Prince, H. Blanch

Michael J. Prince

No abstract provided.