The synthesis and scanning tunneling microscopy (STM) investigations of shape-persistent arylene-ethynylene-butadiynylene macrocycles along with their codeposites with metallacycles are reported. 2D ordered arrays of macrocycles and macrocycle/metallacycle architectures (1:1) have been obtained on HOPG by self-assembly under ambient conditions. It is found that the ordered macrocycle array acts as a template for the deposition of the adlayer molecules. For each underlying macrocycle, one metallacycle has been detected. The unit-cell data of both, the macrocycles and their codeposites, show that the structural information of the macrocycle layer is perfectly transformed to the guest molecules. A rather unexpected observation is that the present compound could not be coadsorbed with C(60), indicating that only a minor change in the structure of the macrocycle has a dramatic effect on the ability of the monolayer to bind additional guest molecules.
In this study, the crosslinked ethylene–propylene–diene
monomer (EPDM) foams were prepared by batch foaming using compressed
CO2 as the blowing agent. The various crosslinking structures,
i.e., the local primary crosslinking structure, the micro-crosslinking
structure, and the full crosslinking structure, were generated by
adjusting the loading of the crosslinking agent. The models were established
to illustrate the fundamental influences of crosslinking structures
on the evolution of cell morphology. EPDM-0.2B with 0.2 parts per
hundred of rubber (phr) loading of the crosslinking agent had the
micro-crosslinking structure, which improved the foamability of EPDM
significantly. The foaming temperature window was broadened from 40–80
to 100–200 °C, and the expansion ratio was increased from
5.6 to 7.1 compared with pure EPDM. Meanwhile, the structure endows
the EPDM-0.2B foam with improved creep resistance, increased thermal
stability, and a melt-recycling ability. The EPDM foam with the full
crosslinking structure exhibited better creep resistance and thermal
stability, but the structure spoiled its melt-recycling ability significantly.
Hybrid supramolecular architectures have been fabricated with acceptor 1,4-bis(4-pyridylethynyl)-2,3-bis-dodecyloxy-benzene (PBP) and donor 2,6-bis(3,4,5-tris-dodecyloxyphenyl)dithieno[3,2-b:2′,3′-d]thiophene (DTT) compounds on highly oriented pyrolytic graphite (HOPG) surfaces and their structures and molecular conductance are characterized by scanning tunneling microscopy/spectroscopy (STM/STS). Stable, one-component adlayers of PBP and DTT are also investigated. The coadsorption of two-component mixtures of PBP and DTT results in a variety of hybrid nanopattern architectures that differ from those of their respective one-component surface assemblies. Adjusting the acceptor/donor molar ratio in mixed adlayer assemblies results in dramatic changes in the structure of the hybrid nanopatterns. STS measurements indicate that the HOMO and LUMO energy levels of PBP and DTT on an HOPG surface are relatively insensitive to changes in the hybrid supramolecular architectures. These results provide important insight into the design and fabrication of two-dimensional hybrid supramolecular architectures.
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