2 research outputs found
High Proton Conduction of Organized Sulfonated Polyimide Thin Films with Planar and Bent Backbones
Fast proton conduction was achieved
in organized lamellar structures
with in-plane oriented structure parallel to the substrate surface
using a lyotropic liquid-crystalline (LC) property. Alkyl sulfonated
polyimides (ASPIs) with bent main chain structure were newly synthesized
to investigate relations between the higher order structure and proton
transport properties. Proton conductivity of all polyimide thin films
was greater than 10<sup>–2</sup> S/cm. Grazing-incidence small-angle
X-ray scattering (GI-SAXS) revealed that both planar and bent ASPI
thin films exhibited humidity-induced lyotropic lamellar structure.
Infrared p-polarized multiple-angle incidence resolution (pMAIR) studies
revealed that main chain backbones of both planar and bent ASPI thin
films show an in-plane orientation parallel to the substrate surface.
Results demonstrate that sulfonated alkyl side chains contribute strongly
to the lyotropic LC property, which enhances molecular orderings and
proton conductivity by water uptake. This study extends knowledge
of the molecular design for highly proton conductive polymers with
humidity-induced lyotropic LC property
Superatom Molecular Orbitals of Endohedral C<sub>82</sub>
Understanding superatom molecular orbital (SAMO) states
in fullerene
derivatives has been in the limelight ever since the first discovery
of SAMOs owing to the fundamental interest in this topic as well as
to the possible applications in molecular switches and other organic
electronics. Nevertheless, very few reports have been published on
SAMO states of larger fullerenes so far. Using density functional
theory, we attempt to partially remedy this situation by presenting
a study on SAMO states in C82 and its Ca and Sc endohedrally
doped derivatives, comparing results with previous relevant findings
for C60. We find that C82 possesses higher SAMO
energies compared to C60, as associated with the symmetry
of the molecule, and that endohedral doping leads to energetically
favorable side positions of Ca and Sc inside the C82 cage.
Among the two, Sc@C82 has more stable SAMO states compared
to Ca@C82 as reflected by the shift in the density of states,
while the charge states are found to be similar. In the case of the
monolayer form, the pz- and 2s-SAMO orbitals
overlap with the nearest neighbors, causing parabolic band dispersion
with the formation of near free electron states and that the SAMO
state energies move closer to the Fermi energy compared to the related
molecules. These findings provide promising information about the
distribution of SAMO states in C82 fullerene, which can
be further relevant in studies of SAMO states of higher fullerenes
and for coming applications of these systems