• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.224-224
• /
• 2015

Gel have enormous applicable region due to inherently high stretchability and bio-compatibility. Here, we fabricated highly stretchable electronic conductive organogels which have long-term stability in environment. By introducing a dialysis step which can incorporate conducting polymer, PEDOT, on the procedure of gel synthesis, residual ions inside the gel were removed. In addition, we replaced the water with organic solvent, EG, inside the gels which is high stability in air. Unlike conventional hydrogels, there are no ionic conduction occurred and electrochemically driven current was prevented during electrical voltage was applied. The fabricated organogels are hardly dried during air exposure, and only electrically conductive without any electrochemical reaction at even high voltage. In order to utilize as stretchable conductor, we demonstrated a LED array circuit using the conductive organogels as electrical interconnects. It was successfully operative even stretched up to 300% strain.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.4
• /
• pp.1258-1262
• /
• 2011

A new organogelator, L-Alanine dihydrazide derivative can self-assemble in various organic solvents and turned them into thermally reversible physical supramolecular organogels at extremely low concentrations (< 2 wt %). The gel-sol phase transition temperatures ($T_{GS}$) were determined as a function of gelator concentration and the corresponding enthalpies (${\Delta}H_g$) were extracted. Scanning electron microscopy (SEM) measurements revealed that the interspaces of fiber-like network structures were diminished with the increasing of the LMOG concentration. FT-IR spectroscopy studies revealed that hydrogen-bonding and hydrophobic interaction were the driving forces for the formation of the gels. Based on the data of XRD and molecular modeling, the possible packing modes for the formation of organogelator aggregates were proposed.

• Journal of Pharmaceutical Investigation
• /
• v.21 no.1
• /
• pp.1-10
• /
• 1991

Hydrogels containing ketoprofen were prepared by adding NaOH or $Ca(OH)_2$ solution to Eudragit L, S and Eudispert hv at various concentration. And xerogels were prepared by drying hydrogels. On the other hand, organogels containing ketoprofen were prepared by mixing Eudragit L or S and propylene glycol. Effects of polymer content and base on drug release were investigated using KP V dissolution method. The release rate of ketoprofen from Eudragit L & S hydrogel decreased with increasing in polymer content. And the drug release rate from cal. hydroxide based gels were more decreased than that from sod. hydroxide based gels. At pH 7.2 dissolution medium, e release of ketoprofen from Edispert hv hydrogel followed apparent zero order kinetics. The release of ketoprofen from xerogel involved in simultaneous absorption of water and desorption of ketoprofen via a pH-dependant swelling controlled mechanism. The release of ketoprofen from Eudragit S organogels followed apparent zero order kinetics, providing strong evidence for a surface erosion mechanism.

• Applied Chemistry for Engineering
• /
• v.29 no.2
• /
• pp.244-247
• /
• 2018

Lecithin, a zwitterionic phospholipid, forms spherical reverse micelles in organic solvents such as decane. The addition of multivalent ions like calcium chloride to lecithin organosols induces the transformation of organosols into organogels. A variety of applications of such organogels were found in gelation of fuels, food processing and drug delivery. Here, we investigated the effect of temperature on their rheological properties. In particular, the organogels showed a distinct melting temperature (${\sim}95^{\circ}C$) and their elastic properties decreased with increasing temperature. This is maybe due to the fact that the electrostatic interaction between lecithin and calcium chloride could be weaken with increasing temperature.

• Journal of Adhesion and Interface
• /
• v.24 no.4
• /
• pp.131-135
• /
• 2023

Lecithin self-assembles into reverse spherical micelles in organic solvents as an amphiphilic molecule. When additives such as bile salts and water are introduced into lecithin solutions, it induces structural changes in the molecular form of lecithin, leading to the transformation into reverse cylindrical micelles. In this study, we observe the rheological changes of lecithin/bile salt mixtures in a decane system after the addition of water. The resulting mixtures exhibit high viscosity and characteristics of viscoelasticity, suggesting potential applications in various fields such as drug delivery and edible oil gels.