Nonplanar
three-fold symmetrical triphenylmethanol (1: n = 10 and 2: n =
3) and triphenylamine (3: n = 10 and 4: n = 3) derivatives bearing three alkylamide
(−NHCOC
n
H2n+1) chains were studied in terms of their phase transitions,
molecular assemblies, nano- or meso-structures, and dielectric responses.
Slight modification of the structural core from a hydroxyl moiety
(C–OH in 1) to a nitrogen atom (N in 3) drastically changed the molecular assembly structures and physical
properties in solids. The molecular assembly of 1 showed
a glass–plastic crystal phase transition at ∼340 K,
whereas 3 only displayed a direct solid–liquid
phase transition. Uniform microscale spheres and nanowires with average
diameters of 2 μm and 200 nm, respectively, were observed for
the molecular assemblies of 1 and 3 on substrate
surfaces, respectively, corresponding to amorphous glass and one-dimensional
hydrogen-bonding columnar structures. An α-type frequency- and
temperature-dependent dielectric relaxation was observed in amorphous 1 during the glass–plastic crystal phase transition,
whereas no dielectric anomalies were observed for 3.
This difference was attributed to the subtle chemical modification
of the central core from C–OH to N.
This study reports a technique to measure the local ve [ ocity near the liquid −liquid interface at high spatia [ resQlution , by using laser radiation pressure . In order to form the interface in a microchannel . the two fluid flow was controlled by the rnodification to the channel walls . The particle was trapped by the laser , and meved to an arbitrary position fbr rneasurement . Two typcs of measurement technique were proposed 二 ( 1 ) PTV measurcment tbr
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