Effect of iron-iron oxide particles on the rate of isomerization of azobenzene moieties in polymeric liquid crystals at air-water interface

• Published in: Colloid and polymer science 2021-04, Vol.299 (4), p.603-609
• Main Authors: Raghavendra, Gupta, Satyam Kumar, Kumar, Bharat
• Format: Article
• Language: English
• Subjects: Azo compounds; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Food Science; Iron oxides; Isomerization; Liquid crystal polymers; Liquid crystals; Monomolecular films; Nanotechnology and Microengineering; Original Contribution; Physical Chemistry; Polyethylene glycol; Polymer Sciences; Soft and Granular Matter
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-020-04776-4

We have studied the effect of iron-iron oxide particles on the trans-cis isomerization of azobenzene moieties in the novel polyethylene glycol itaconate-azobenzene based side chain liquid crystalline polymer (PEGIA). Langmuir monolayers of the PEGIA molecules are spread at air-water interface, with water subphase containing different concentrations of iron-iron oxide particles. The kinetics of the isomerization of azobenzene moieties in the polymer was studied by surface manometry technique. We find that the presence of iron-iron oxide particles in the subphase affects the rate constant of trans-cis photoisomerization and it decreases exponentially as a function of concentration of particles in the subphase. The critical concentration of iron-iron oxide particles above which the rate constant of photoisomerization negligibly changed was found to be about 2.468 μg cm − 3 .