Polydiacetylene/Silica Nanocomposites with Tunable Mesostructure and Thermochromatism from Diacetylenic Assembling Molecules

Abstract

Conjugated polydiacetylene (PDA)/silica nanocomposites with tunable mesostructures and reversible thermochromatism were synthesized through self-directed assembly of diacetylenic silanes. In contrast to the previous studies, where the PDA side chains interacted weakly through noncovalent interactions, the side chains in the present nanocomposites are covalently connected to the inorganic silica frameworks, providing control over the molecular alignment, stability, and electronic properties. Furthermore, tuning the molecular architecture (e.g., the shape and side-chain length) allows control over the mesostructure (e.g., cubic and lamellar) and chromatic response of the nanocomposites (from irreversible to partially reversible and then to completely reversible). As a result of the covalent interactions, the nanocomposites also demonstrate higher reversible chromatic transition temperatures. This work not only provides responsive robust chromatic materials toward practically reusable PDA sensors but also is of great fundamental value for the design of supramolecular assembly and the understanding of the chromatic mechanism of PDA.

Luminescent Triazine‐Containing Bridged Polysilsesquioxanes Activated by Lanthanide Ions

“…[13,14] To date, great effort has been directed to optical applications of bridged polysilsesquioxanes by incorporating various chromospheres in the bridging groups. [15][16][17][18] The use of dye molecules as bridging groups offers a high loading of chromospheres and avoids the leaching or phase separation of the dye molecule. However, there are relatively few studies on the preparation of luminescent polysilsesquioxanes with lanthanide complexes as the bridging group.…”

Squarely Mesoporous and Functional Nanocomposites by Self‐Directed Assembly of Organosilane

“…Furthermore, the hybrid nanocomposites provide improved thermal stability. [24,27] As shown in Figure 5b, the porphyrin precursor undergoes bulk decomposition at about 500°C, while the nanocomposites lose the bulk weight at much higher temperature (∼ 800°C).…”

“…The versatile optical and electrochemical properties, the possibility to tune these properties by grafting various substituents at their peripheral positions, and their high chemical and thermal stabilities make porphyrin families attractive materials in electronics, optoelectronics, and photonics. [23] For the currently engineered nanocomposites, the ordered silica network provides a much improved alignment for the p-p stacking of the porphyrin moieties, [24,25] favoring a better optoelectronic performance of the conjugated systems. As expected, the UV-vis spectra of porphyrin/silica fibers are significantly different from those of the corresponding PBS solutions.…”

Spectroscopy of Polyaniline Nanofibers

“…(2) is constituted by polymers with cyclopentadiene ring containing a hetero atom: (e) poly(pyrrole), (f) poly(thiophene), (g) poly(furan), and (h) poly(heteroaromatic-vinylene) (where Y = NH, NR, S, O). Finally, the Group (3) is formed by acetylene units, being (i) poly(acetylene) and (j) poly(di-acetylene) (where R 1 and R 2 can be a large variety of organic groups (Song et al, 2004;Asefa et al, 1999;Peng et al, 2005)) the most important ones.…”