Silica aerogel has a variety of excellent properties, but the mechanical brittleness inhibits the practical applications. Recently, many experimental efforts have been made to improve the compressibility and bendability of aerogels by hybridization with organic materials; however, the reason of the flexibility has not yet been well understood. To identify the intrinsic origins of the flexibility of organic− inorganic hybrid aerogels, polymerization and mechanical responses of tetramethoxysilane (TMOS), methyltrimethoxysilane (MTMS), and 1,2-bis(methyldiethoxysilyl)ethane (BMDEE) polymers were investigated by using reactive molecular dynamics simulations. As a result, cyclic compressive deformation simulations successfully reproduce the experimental results that TMOS is substantially fragile, whereas MTMS and BMDEE are easy to be reshaped. Detailed structure analyses showed that Si−O−Si−O rings in TMOS are collapsed by compressive deformation, whereas any kind of ring structure in BMDEE is maintained even after large compression. Tetrahedral SiO 4 -based network structure (Q 4 ) in TMOS is found to be the source of the brittleness. On the contrary, the absence of Q 4 silicones and the presence of ethylene units, which provide rotatable dihedrals, in BMDEE allow it to deform without disrupting the microscale network. The insightful information provided by the theoretical investigation in atomistic scale is essential to design new composite aerogels.

A perfluorinated graded index polymer optical fiber (PFGI-POF) has been developed and manufactured for data communication to provide a high bandwidth with easy termination and cabling. In the PFGI-POF technology, the graded refractive index profile using dopants is a key technology to obtain a high bandwidth, excellent transparency and thermal durability. This study of the dopant selection for the PFGI-POF is reported for the first time.

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A series of tetrakis(alkylthio)tetraselenafulvalene compounds (TTCn-TSeF, n = 1–15) were prepared by a one-step reaction between dialkyl disulfide and tetralithiated TSeF. Molecular properties (redox potentials and optical absorptions in solution) and solid-state properties (thermal behaviors, electric conductivities, and molecular and crystal structures for n = 1 and 10) were studied. TTCn-TSeF compounds are weak electron donor molecules and characterized by small on-site Coulomb repulsion. TTC1-TSeF has a high-dimensional conduction network owing to the presence of high-dimensional heteroatomic contacts, “Atomic-Wire Effect.” The π-moieties of TTC10-TSeF were fastened by the alkyl chains (“Fastener Effect”) to form π-columns and there are a variety of short heteroatomic contacts resulting in two-dimensional electronic structure. Electrical conductivity exhibited peculiar enhancement for n = 1 and 7 ≤ n ≤ 14 owing to the presence of high-dimensional conduction paths. These compounds may manifest high carrier mobility, and are good candidates for the field-effect transistor channel based on the advantageous features: low dark conductivity, low donor ability, on-site Coulomb repulsion energy, high-dimensional π-electron structure, and high solubility in organic solvents.

A flexible aerogel polymerized from methyltrimethoxysilane (MTMS) shows great promise as a high-performance insulator owing to its substantially low thermal conductivity and mechanical flexibility, attributed to its porous microstructure and...