Invited Lecture. Ferroelectric liquid crystalline polymers and related model compounds with a low–moderate degree of polymerization

Abstract

Ferroelectric liquid crystalline polymers (FLCPs) with a low-moderate degree of polymerization were synthesized. These had a comb structure; the main chain was polyacrylate and the side chain consisted of a flexible spacer, a core and an optically active chiral end group. They exhibited electro-optic switching times ranging from a few milliseconds to a few seconds in the S*_c phase. As the molecular weight M _n increased, the range of the S*_c shifted to higher temperatures. At a given temperature, the switching time increased with M _n .

Spontaneous polarizations P _s , apparent cone angles 2θ, electro-optic switching times τ and rotational viscosities η of some polyoxyethylene FLCPs and corresponding low molecular weight ferroelectric liquid crystal materials (FLCs) were also measured. This is the first report of polyoxyethylene FLCPs. There was no significant difference in P _s and 2θ, which shows that the arrangement of the side chains in the FLCP is similar to that of the molecules in ordinary FLC. On the contrary, τ and η for the FLCPs were 10²–10³ times as large as those for FLCs. The rotational viscosity of the FLCP was mainly dependent on the side chain structure rather than on the spacer. Therefore collisions between adjacent side chains cause large η values in FLCPs rather than hindrance to side chain gyration due to the spacer group. By combining FLCPs with ITO-coated plastic substrates, a large area matrix driven display has been made. Although an improvement in switching time is still needed, a flexible and lightweight display like a sheet of paper will be available in the near future.     

Sputtering angle effects by Kr mixing in N+ ion beam on the lifetime of nitrided carbon stripper foils

Nitrided carbon stripper (NCS) foils with high nitrogen content were produced by ion beam sputtering of reactive nitrogen gas. Such foils seem to be very useful as strippers in high-intensity heavy ion accelerators. We have conducted comprehensive research, development, and production of such foils with high reproducibility. Krypton, a heavy noble gas, was mixed with the reaction nitrogen gas (IBSRN) in the ion beam sputtering process to produce stripper foils with short sputtering deposition time and long lifetimes in the high intensity ion beam irradiation. With the (N₂ + Kr) mixed gas ions we investigated the influence of different sputtering angles (α) on the lifetime of the NCS-foils in case of poly-graphite material. The lifetime measurement of these foils of 20 ± 5 μg/cm² was performed with a 3.2 MeV Ne⁺ ion beam as usual. The foils made at a sputtering angle of 15° showed a maximum of 11.0 and 7.5  C/cm² average charge density, respectively, which corresponded to about 275 and 187 times the lifetime of the best commercially available foils.     

Progress in Molecular Nanoarchitectonics and Materials Nanoarchitectonics

Although various synthetic methodologies including organic synthesis, polymer chemistry, and materials science are the main contributors to the production of functional materials, the importance of regulation of nanoscale structures for better performance has become clear with recent science and technology developments. Therefore, a new research paradigm to produce functional material systems from nanoscale units has to be created as an advancement of nanoscale science. This task is assigned to an emerging concept, nanoarchitectonics, which aims to produce functional materials and functional structures from nanoscale unit components. This can be done through combining nanotechnology with the other research fields such as organic chemistry, supramolecular chemistry, materials science, and bio-related science. In this review article, the basic-level of nanoarchitectonics is first presented with atom/molecular-level structure formations and conversions from molecular units to functional materials. Then, two typical application-oriented nanoarchitectonics efforts in energy-oriented applications and bio-related applications are discussed. Finally, future directions of the molecular and materials nanoarchitectonics concepts for advancement of functional nanomaterials are briefly discussed.     

Observation of two resonant structures in e+ e- -->pi+ pi- psi(2S) via initial-state radiation at Belle

The cross section for e+ e- --> pi+ pi- psi(2S) between threshold and sqrt[s]=5.5 GeV is measured using 673 fb(-1) of data on and off the Upsilon(4S) resonance collected with the Belle detector at KEKB. Two resonant structures are observed in the pi+ pi- psi(2S) invariant-mass distribution, one at 4361 +/- 9 +/- 9 MeV/c2 with a width of 74 +/- 15 +/- 10 MeV/c2, and another at 4664 +/- 11 +/- 5 MeV/c2 with a width of 48 +/- 15 +/- 3 MeV/c2, if the mass spectrum is parametrized with the coherent sum of two Breit-Wigner functions. These values do not match those of any of the known charmonium states.     

Measurement of Einstein-Podolsky-Rosen-type flavor entanglement in Upsilon(4S) --> B0 B0 decays

The neutral B meson pair produced at the Upsilon(4S) should exhibit a nonlocal correlation of the type discussed by Einstein, Podolsky, and Rosen. We measure this correlation using the time-dependent flavor asymmetry of semileptonic B(0) decays, which we compare with predictions from quantum mechanics and two local realistic models. The data are consistent with quantum mechanics, and inconsistent with the other models. Assuming that some B pairs disentangle to produce B(0) and B(0) with definite flavor, we find a decoherent fraction of 0.029 +/ -0.057, consistent with no decoherence.     

Measurements of branching fractions for B --> K pi and B --> pi pi decays

We report measurements of branching fractions for B --> K pi and B --> pi pi decays based on a data sample of 449 x 10(6) BB[over] pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We also measure the ratios of partial widths for B-->Kpi decays, namely R(c) identical with 2Gamma(B(+) --> K(+) pi(0))/Gamma(B(+) --> K(0) pi(+)) = 1.08+/-0.06+/-0.08 and R(n) identical with Gamma(B(0) --> K(+) pi(-))/2 Gamma(B(0) --> K(0) pi(0)) = 1.08+/-0.08+/-0.08, where the first and the second errors are statistical and systematic, respectively. These ratios are sensitive to enhanced electroweak penguin contributions from new physics; the new measurements are, however, consistent with standard model expectations.     

Observation of a charmoniumlike state produced in association with a J/psi in e+e- annihilation at sqrt[s] approximately equal to 10.6 GeV

We report the first observation of a charmoniumlike state recoiling from the J/psi in the inclusive process e+e- -->J/psi+anything at a mass of (3.943+/-0.006+/-0.006) GeV/c{2}. We also observe the decay of this state into D*D[over ] and determine its intrinsic width to be less than 52 MeV/c{2} at the 90% C.L. These results are obtained from a 357 fb{-1} data sample collected with the Belle detector near the Upsilon(4S) resonance, at the KEKB asymmetric-energy e+e- collider.     

Exciton transfer between localized states in ZnO quantum well structures

The dynamics of photocreated excitons in a CdZnO/MgZnO quantum well (QW) was studied by comparing the experimental photoluminescence (PL) data with the results of Monte Carlo simulations of the exciton hopping. The temperature-dependent PL linewidth was found to be in reasonable agreement with the model of exciton hopping, with an additional inhomogeneous broadening (Γ) accounted for. The simulation analysis revealed fluctuations of the band potential to be 20 meV with an additional inhomogeneous broadening of , and a crossover from a non-thermalized to thermalized exciton energy distribution at about 100 K. In addition, a Bose–Einstein distribution like temperature dependence of the exciton energy in the wells was extracted using the data on the PL peak position.     

Self‐Replication and Amplification of Enantiomeric Excess of Chiral Multifunctionalized Large Molecules by Asymmetric Autocatalysis

Self‐replication of large chiral molecular architectures is one of the great challenges and interests in synthetic, systems, and prebiotic chemistry. Described herein is a new chemical system in which large chiral multifunctionalized molecules possess asymmetric autocatalytic self‐replicating and self‐improving abilities, that is, improvement of their enantioenrichment in addition to the diastereomeric ratio. The large chiral multifunctionalized molecules catalyze the production of themselves with the same structure, including the chirality of newly formed asymmetric carbon atoms, in the reaction of the corresponding achiral aldehydes and reagent. The chirality of the large multifunctionalized molecules controlled the enantioselectivity of the reaction in a highly selective manner to construct multiple asymmetric stereogenic centers in a single reaction.