ABD-grafted PMMA

Two types of ABD-grafted PMMA were initially prepared with different polar and electronic substituents (Fig. 2). ABD-grafted polymer 1 contains no substituent in the azobenzene para position while polymer 2 contains a para nitro group. Potentially, two synthetic routes are possible to generate ABD-grafted PMMA. In approach PMMA is first synthesized and then the ABD is grafted onto the polymer chains. In another approach, ABD-grafted methylmethacrylate monomer units are first synthesized and then polymerized in a subsequent step. 

Reaction progress was monitored using IH-NMR and the optical activity of the ABD-grafted PMMA, MMA, and of model compound 9 was verified by collecting UV-vis absorbance spectra in solution. All compounds were initially prepared in approximately 5 g batches. Approximately 50 g batches of compound 1 was later prepared with no significant procedural modifications. 

All the ABD-grafted PMMA showed optical response in methylene chloride solutions (Fig. 4). 

Figure 5- (A) Trans to cis isomerization of a film of ABD-grafted PMMA 1 and, (B) cis to trans isomerization of 1 with visible light.

Figure 2. Expected photoinduced isomerization of ABD grafted onto PMMA. ...

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