For practical application of self-assembled monolayers (SAMs), knowledge of their chemical durability in acidic or basic solutions is important. In the present work, a series of SAMs directly immobilized on a silicon (111) surface through Si-C or Si-O-C covalent bonds without a native oxide layer were prepared by thermally activated chemical reactions of a hydrogen-terminated Si(111) substrate with linear molecules, i.e., 1-hexadecene, 1-hexadecanol, 1-dodecanol, and n-dodecanal, to investigate the durability of the SAMs to HF and Na2CO3 solutions. While grazing incidence X-ray reflectivity measurements showed that all the as-prepared SAMs had almost the same film density and molecular coverage, keeping the original step and terrace structure of Si(111) as is observed by atomic force microscopy, they gave different degradation behaviors, i.e., pitting and concomitant surface roughening in both solutions. 1-hexadecene SAM was stable against immersion in both solutions, while the other SAMs were damaged within 60 min, most likely due to the difference in chemical bonding modes at the SAM/Si interface, i.e., Si-C and Si-O-C.

Chemically converted graphene (CCG) covalently linked with porphyrins has been prepared by a Suzuki coupling reaction between iodophenyl-functionalized CCG and porphyrin boronic ester. The covalently linked CCG-porphyrin composite was designed to possess a short, rigid phenylene spacer between the porphyrin and the CCG. The composite material formed stable dispersions in DMF and the structure was characterized by spectroscopic, thermal, and microscopic measurements. In steady-state photoluminescence spectra, the emission from the porphyrin linked to the CCG was quenched strongly relative to that of the porphyrin reference. Fluorescence lifetime and femtosecond transient absorption measurements of the porphyrin-linked CCG revealed a short-lived porphyrin singlet excited state (38 ps) without yielding the porphyrin radical cation, thereby substantiating the occurrence of energy transfer from the porphyrin excited state to the CCG and subsequent rapid decay of the CCG excited state to the ground state. Consistently, the photocurrent action spectrum of a photoelectrochemical device with a SnO(2) electrode coated with the porphyrin-linked CCG exhibited no photocurrent response from the porphyrin absorption. The results obtained here provide deep insight into the interaction between graphenes and π-conjugated systems in the excited and ground states.

A remanent polarization of 130Ϯ3 mC/m 2 , large among the values reported for organic materials, and rectangular D -E hysteresis curves were realized in synthesized vinylidene fluoride ͑VDF͒ oligomer ͓CF 3 (CH 2 CF 2 ) 17 I͔ film evaporated onto a platinum surface around liquid nitrogen temperature. The results suggested that the VDF oligomer film has an extremely high crystallinity, and the electric dipoles arrange almost perfectly perpendicular to the film surface, and that a Lorentz local field factor of ferroelectric VDF oligomer crystals is nearly zero. Moreover, the obtained value of the coercive field, which was larger than those of ferroelectric polymers, might be attributed to the steric hindrance arising from the existence of iodine atoms at the VDF oligomer chains.

Golden viruses: The rodlike tobacco mosaic virus and citrate‐covered gold nanoparticles of 6‐nm diameter self‐assemble into a metal‐virus nanodumbbell. The gold nanoparticles selectively bind to the ends of the rods, and can be enlarged by electroless deposition to yield gold‐virus‐gold dumbbells (see picture).