Tribology of Pore-Textured Hard Surfaces under Physiological Conditions: Effects of Texture Scales
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Engineering topics
Choi, Chang-Hwan
Publications and source records attributed to Choi, Chang-Hwan.
Orienting and shaping organic semiconductor single crystals through selective nanoconfinement
Nanoconfining scaffolds can be used to orient and shape organic semiconductor crystals during solution-phase crystallization depending on the scaffold geometry and the native crystal growth habit.
Alaei, Aida↗
Nanoconfinement and Salt Synergistically Suppress Crystallization in Polyethylene Oxide
Suppressing the crystallization of polyether-based solid electrolytes is a widely sought-after strategy to improve ionic conductivity. We report the effects of nanoconfinement on polyethylene oxide electrolytes. We find that neat polyethylene oxide responds to nanoconfinement by adopting a preferred orientation, yet is able to crystallize even in nanoconfinement volumes with widths as small as 8 nm. However the combination of nanoconfinement and salt addition does suppress polymer crystallization at room temperature, even though either factor alone cannot. Such synergistic suppression of crystallization has implications for polymer electrolytes, since amorphous rather than crystalline domains predominantly contribute to ionic conduction. Our results suggest that salts previously discounted due to their inability to suppress crystallinity in bulk materials could be made viable when combined with nanoconfinement, thereby opening new possibilities for high-performance solid polymer electrolytes.
36 MATERIALS SCIENCE↗
Nanoscale viscosity of confined polyethylene oxide
Complex fluids near interfaces or confined within nanoscale volumes can exhibit substantial shifts in physical properties compared to bulk, including glass transition temperature, phase separation, and crystallization. Because studies of these effects typically use thin film samples with one dimension of confinement, it is generally unclear how more extreme spatial confinement may influence these properties. In this work, we used x-ray photon correlation spectroscopy and gold nanoprobes to characterize polyethylene oxide confined by nanostructured gratings (<100nm width) and measured the viscosity in this nanoconfinement regime to be ~500 times the bulk viscosity. Here, this enhanced viscosity occurs even when the scale of confinement is several times the polymer's radius of gyration, consistent with previous reports of polymer viscosity near flat interfaces.
36 MATERIALS SCIENCE↗