Synthesis and characterization of polymethacrylates containing conjugated oligo(phenylene ethynylene)s as side chains

Abstract

In order to form suitable systems designed for resonance energy transfer, a series of monodisperse methacrylate‐based monomers containing rigid π‐conjugated oligo(phenylene ethynylenes) with different sizes of the conjugated systems (M1–M3), and therefore different optoelectronic properties, were synthesized and subsequently polymerized using the reversible addition–fragmentation chain transfer polymerization technique (P1–P3). In addition, these oligomers were also copolymerized with methyl methacrylate. The obtained polymers were characterized by 1H NMR spectroscopy, size exclusion chromatography, and analytical ultracentrifugation. The photophysical properties of the polymers were studied by UV–vis absorption and emission spectroscopy in diluted solutions as well as in thin films and compared to the photophysics of the corresponding monomers. Thereby, changes going from monomeric to polymeric systems could be detected in fluorescence quantum yields and lifetimes pointing to energy trapping, e.g., energy transfer. Donor–acceptor copolymers containing different numbers of monomeric units within the side chain exhibit differences in the emission spectra, indicating that energy trapping in polymers is very sensitive to structural properties such as the chain length. UV–vis absorption spectroscopy as well as time‐resolved lifetime studies indicate intrapolymer and interpolymer energy transfer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Photophysics of a Bis‐Furan‐Functionalized 4,7‐bis(Phenylethynyl)‐2,1,3‐benzothiadiazole: A Building Block for Dynamic Polymers

“…Excitation spectra recorded at λ em =520 nm were basically identical to the absorption spectrum, which is indicative of a single emitting species (Figure S1). Notably, the emission quantum yield Φ F,M is near unity and larger than recorded for structural analogues ,–,…”

“…First, the photophysics of the monomer M is discussed in detail, beginning with steady‐state absorption and emission spectroscopy in solution (Figure , Table ). The visible part of the absorption spectrum recorded in CHCl 3 is characterized by a maximum centered at λ abs,M =418 nm with a moderate absorption coefficient, ϵ max =25 ⋅ 10 3 M −1 cm −1 , comparable to mono‐furan substituted or methylacrylate‐functionalized BAE‐BTDs ,. The emission spectrum exhibits a maximum at λ em,M =516 nm and is mirror symmetric to ϵ ( λ ) with respect to the lowest energy absorption band.…”

“…In particular, the effect of the polymerization of M on photophysical properties of the chromophore was not discussed. This is, however, of particular importance, as it has already been demonstrated, that a high chromophore concentration of AEs attached as side‐chains to an aliphatic backbone leads to different excited state decay pathways, e. g., homo‐energy transfer between adjacent chromophores, which is detrimental to the emission quantum yield ,. Due to the short bis‐maleimide linker used (Scheme ), whose length is in the order of 15 Å, similar effects might play a role in main‐chain polymers as well.…”

Progress in side-chain thiophene-containing polymers: synthesis, properties and applications

“…Due to the space limitation, we review only the examples of thiophene based building blocks as a representative because of its ease and diversity on chemistry. Plenty of work on other conjugated building blocks has also been reported [20,23,25,[29][30][31]69,70], and attracted increasing attention. The development on the synthesis of conjugated/non-conjugated bi-functional materials would enhance the properties of current products, and emerging applications will enable these materials a bright future.…”

“…This review will be limited to non-conjugated polymers with thiophene-based oligomers as pendant groups. There is an abundance of work in which other conjugated oligomers (e.g., perylene bisimides (PBIs) and related molecules [20,29,30] and oligo-(phenylene ethynylene)s [23,31]) are present as pendant groups or thiophene oligomers are pendant in conjugated polymers [32][33][34]; however, all these works are beyond the scope of this review.…”