Browsing by Author "Altukhov, Oleksii"

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Supramolecular Functionalities Influence the Thermal Properties, Interactions and Conductivity Behavior of Poly(ethylene glycol)/LiAsF6 Blends
(2013-09-01)
Wang, Jui-Hsu
;
Cheng, Chih-Chia
;
Altukhov, Oleksii
;
Chang, Feng-Chih
;
Kuo, Shiao-Wei
In this study, we tethered terminal uracil groups onto short-chain poly(ethylene glycol) (PEG) to form the polymers, uracil (U)-PEG and U-PEG-U. Through AC impedance measurements, we found that the conductivities of these polymers increased upon increasing the content of the lithium salt, LiAsF6, until the Li-to-PEG ratio reached 1:4, with the conductivities of the LiAsF6/U-PEG blends being greater than those of the LiAsF6/U-PEG-U blends. The ionic conductivity of the LiAsF6/U-PEG system reached as high as 7.81 x 10(-4) S/cm at 30 degrees C. Differential scanning calorimetry, wide-angle X-ray scattering, Li-7 nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy revealed that the presence of the uracil groups in the solid state electrolytes had a critical role in tuning the glass transition temperatures and facilitating the transfer of Li+ ions.
Supramolecular structures of uracil-functionalized PEG with multi-diamidopyridine POSS through complementary hydrogen bonding interactions
(2013)
Wang, Jui-Hsu
;
Altukhov, Oleksii
;
Cheng, Chih-Chia
;
Chang, Feng-Chih
;
Kuo, Shiao-Wei
In this study, we synthesized (i) a multi-diamidopyridine-functionalized polyhedral oligomeric silsesquioxane (MD-POSS) through nucleophilic substitution and click 1,3-cycloaddition reactions and (ii) both mono- and bis-uracil (U)-functionalized poly(ethylene glycol) derivatives (U-PEG and U-PEG-U, respectively) through Michael additions of U to acryloyl-functionalized PEG oligomers. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed that supramolecular structures self-assembled from mixtures of MD-POSS and U-PEG and from MD-POSS and U-PEG-U. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed the presence of multiple hydrogen bonding interactions between the diaminopyridine groups of MD-POSS and the U groups of U-PEG and U-PEG-U. Because of these strong reversible intermolecular multiple hydrogen bonds, the POSS-based polymer-like supramolecular materials exhibited improved thermal properties upon increasing the MD-POSS content.