It is known that lecithin, a zwitterionic phospholipid, self-assembles into spherical reverse micelles in organic solvents. We have explored the effects of adding inorganic salts to lecithin organosols. Salts are insoluble in organic solvents, and hence their effects on reverse self-assembly have rarely been studied. Our studies show, however, that salts can indeed be dissolved in organic liquids in the presence of lecithin. More interestingly, salts of multivalent cations like calcium (Ca(2+)), magnesium (Mg(2+)), lanthanum (La(3+)), and cerium (Ce(3+)) greatly increase the viscosity of lecithin organosols and transform the samples into optically transparent organogels. In comparison, monovalent cations or transition-metal cations have negligible effect on reverse self-assembly. On the basis of data from small-angle neutron scattering (SANS), we show that gelation is accompanied by a nanostructural transition from spherical micelles to cylindrical micelles/filaments. The varying abilities of different cations to induce gelation is shown to correlate with their binding tendencies to the phosphocholine headgroups of lecithin. A two-component gelator such as lecithin/Ca(2+) could be attractive for applications due to its negligible cost and nontoxic nature. We demonstrate how such a gelator combination can convert a liquid fuel such as kerosene into a gel without the use of heat or shear. The same gel can also further be ungelled by addition of a few drops of alcohol.
Novel poly(p-phenylenevinylene) derivatives with an electron-withdrawing cyanophenyl
group on the polymer backbone, poly[2-(2‘-ethylhexyloxy)-5-(4‘-cyanophenyl)-1,4-phenylenevinylene]
(PEHCNPV) and poly[2-dimethyloctylsilyl-5-(4‘-cyanophenyl)-1,4-phenylenevinylene] (PSi8CNPV), were
synthesized via the Gilch polymerization. These polymers were completely soluble in common organic
solvents and showed good thermal stability up to 400 °C. Surprisingly, they showed very high glass
transition temperatures (above 180 °C), indicating that electroluminescenece (EL) devices constructed
from these polymers should have good thermal stability. The presence of the electron-withdrawing
cyanophenyl group lowered the HOMO and LUMO energy levels of PEHCNPV and PSi8CNPV relative
to those of common PPV derivatives. Light-emitting diodes (LEDs) with the configuration ITO/PEDOT/polymer/LiF/Al were fabricated using the novel polymers. The LED devices based on PEHCNPV and
PSi8CNPV exhibited maximum electroluminescence at 546 and 513 nm, respectively. In particular, the
LED device containing PSi8CNPV emitted pure green light with a CIE (Commission Internationale de
L'Eclairage) chromaticity coordinate of (0.330, 0.599), which is very close to that of the standard green
(0.30, 0.60) used for high definition television (HDTV), a maximum external quantum efficiency of 0.67%,
and a maximum brightness of 2900 cd/m2.
A charge trapping layer that is separated from the primary gate dielectric is implemented on a FinFET SONOS structure. By virtue of the reduced effective oxide thickness of the primary gate dielectric, a strong gate-to-channel coupling is obtained and thus short-channel effects in the proposed device are effectively suppressed. Moreover, a high program/erase speed and a large shift in the threshold voltage are achieved due to the improved charge injection by the reduced effective oxide thickness. The proposed structure has potential for use in high speed flash memory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.