Surface plasmon resonance studies on spin coated films of azobenzene-substituted calix-4-resorcinarene molecules

Thin films of tetra-undecyl-tetra-p-nitrophenylazocalix(4)resorcinarene (Az ol) molecules were deposited on different substrates by the spin coating me thod. The refractive index of spun films is found to be 1.494 from surface plasmon resonance (SPR) experiments on the sample in contact with two diffe rent dielectric media: air and high purity water. The thickness of films de creases with the increase in the spin speed as a -2/3 power law but rises l inearly with the concentration. These observations are in agreement with hy drodynamic theory for spinning of a low-viscosity and highly volatile liqui d.