Chain polymers carrying aromatic side

Intramolecular Excimer Fluorescence Studies in Polymers Carrying Aromatic Side Chains. Some years ago, it was shown that certain excited aromatic molecules may form a complex with a similar molecule in the ground state, which is characterized by a structureless emission band red-shifted relative to the emission spectrum of the monomer. The formation of such complexes, called "exclmers", requires the two chromophores to lie almost parallel to one another at a distance not exceeding about 3.5A° (11). Later, it was found that Intramolecular excimer formation is also possible. In a series of compounds of the type C5H (CH2)jiC H5, excimer fluorescence, with a maximum at 340nm, was observed only for n 3 -all the other compounds had emission spectra similar to toluene, with a maximum at about 280nm (12). Similar behavior was observed in polystyrene solutions, where the phenyl groups are also separated from one another by three carbon atoms (13). 

In 2014, Li, Hou, and co-workers synthesized a hydrazide polymer that mimics the ion transport of Gramicidin A. ° This polymer carried phenylalanine side chains, which allowed the polymer to be inserted into a lipid bilayer at low concentrations. Patch clamp experiments showed that this polymer could transport some alkali-metal ions such as Na , K , and also NH4 across the membrane. Patch-current traces up to 15 s showed that the structure was stable within the bilayer. As the NH4 selectivity was higher than that for K, the inner pore was estimated to be smaller than 1 nm. Another field where helical polymers have been used is the Space-Charge-Limited Current (SCLC) hole mobility. In 2015, a discotic polycyclic aromatic... 

Lafitte, B. Jaimasch, P. Proton-conducting aromatic polymers carrying hypersulfonated side chains for fuel cell applications. Adv. Funct. Mater. 2007,17, 2823-2834. 

To date, much effort has been undertaken to develop new alternatives. For example, sulfonated aromatic polymers, i.e., polymers with the sulfonic acid groups directly attached to the main chain or carrying short pendant side chains with terminal sulfonic acid units, attract increasing interest because of their chemical and thermal stability, and the ease of the sulfonation procedure. Some of the proposed polymers are sulfonated polysulfone (SPSU) [134] sulfonated poly(phenylene oxide) (SPPO) [135] sulfonated poly-(ether ether ketone) (SPEEK) [136] poly(phenylquinoxaline) (PPQ) [137] and poly(benzeneimidazole) (PBI) [138],... 

Polypeptides carrying aromatic chromophores on their side chains are a new class of chromophoric polymers which may show the following characteristic features (1 ). (1) In principle, one can... 

Lafitte, B., Jannasch, P. (2007) Proton-conducting aromatic polymers carrying hyper-sulfonated side chains for fuel cell apphcations. Advanced Functional Materials, 17, 2823-2843. 

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