Non-topochemical Cross-linking of Amorphous Aliphatic Diacetylene-Containing Polymers

Abstract

In order to demonstrate that the cross-linking of diacetylene-containing polymers depends on the morphology of the polymers, the cross-linking of amorphous aliphatic diacetylene-containing polymers is investigated. It was found that amorphous aliphatic diacetylene-containing polymers underwent cross-linking at room temperature in the solid state without irradiation, incorporating oxygen into the polymers. FT-IR spectra and elemental analysis gave evidence of formation of carbonyl and hydrogen peroxide groups during cross-linking. The cross-linking depended on the types of polymer main chains and also how the polymer molecules are accommodated in the solid. For example, slowly cast thick films underwent cross-linking rapidly, while the cross-linking of fibrous polymers precipitated from the solution was slow or negligible, indicating that the dense packing is an important factor for cross-linking. The mechanism of such crosslinking is discussed.

Cross-Linking of Poly(arylenebutadiynylene)s and Its Effect on Charge Carrier Mobilities in Thin-Film Transistors

“…However, there was indeed cross-linking of the pDET films at the random π–π stacking positions in the film. A similar 1,4-coupling of butadiynes was demonstrated for amorphous polymers, such as poly­(α,ω-alkyldiyne)­s and various other non-conjugated polymers. , …”

“…A similar 1,4-coupling of butadiynes was demonstrated for amorphous polymers, such as poly(α,ωalkyldiyne)s 29 and various other non-conjugated polymers. 30,31 Tapping mode AFM images of the as-cast pDET film exhibited aggregated structures that combine into randomly oriented larger domains (Figure 6a). Upon UV irradiation, fine sub-structures were formed on the surface of the film, leading to an increase in the root-mean-square (rms) surface roughness from 0.26 to 0.52 nm (Figure 6b).…”

“…The main limitation of this approach is that UV-induced polymerization is less likely to occur due to the necessary energy for the reorganization of the main chain backbones. Thus, cross-linking of several amorphous non-conjugated polymers containing butadiyne moieties under UV irradiation was demonstrated, − while similar examples for poly­(arylenebutadiynylene)­s is scarce. The drawback of this method for fully conjugated poly­(arylenebutadiynylene)­s is the twist resulting from the formed PDA, which is tilted with respect to the π-conjugated backbone of the main chain, resulting in disruption of the conjugation.…”