Mixed mono- and multilayers of poly(isocyanide)s with non-linear optically active side chains

Abstract

Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractThe properties and structure of Langmuir-Blodgett mono-and multilayers of several poly(isocyanide)s with non-linear optically active side-chains were studied. These polymers formed very rigid layers or layers which appeared to be unstable. To circumvent this problem they were mixed with other poly(isocyanide)s or with amylose-butyrate. Transmission electron microscopy studies of the polymeric mixtures revealed that phase separation occurred in all cases and that only poly(isocyanide)s substituted with hydrophilic side chains formed monomolecular layers. Depending on the nature of the polymer which was used for mixing, the dye polymers could be deposited with Y-or Z-type transfer. Second-harmonic intensities generated from these films were small in the case of the Y-type multilayered films and moderately high in the case of the Z-type films.

Second-Harmonic Generation from Floating Monolayers and Langmuir−Blodgett Multilayers of Poly(isocyanide)s

“…At a low surface pressure these domains are smaller and less numerous than at a higher surface pressure. This explanation would be in agreement with the morphology of the floating film, as revealed by electron microscopy 12 for the comparable polymer 10.…”

“…For the calculations it was assumed that the monolayer thicknesses of polymers 8 and 9 were the same as those of polymer 10, i.e., 2.73 nm. 12 The fact that the nitro group which is present in polymer 10 is completely buried within the side chains makes this assumption valid.…”

“…Such regions may arise if the floating layer forms thick fluid-like droplets or when it is in a collapsed state. 12 LB Multilayers. The NLO activities of films of polymers 8 and 9 and mixed films of 10 and AB were determined by measuring the second-harmonic intensity generated by multilayered samples on glass substrates.…”

Linearly polarized probes of surface chirality

“…These polyisocyanides form rigid-rod helices on a water surface and can be easily transferred to a solid substrate by means of the LangmuirBlodgett method. 13 The sample used consists of 18 layers of z-type deposited films and is slightly absorbing at the second-harmonic frequency. The fundamental beam of a Q-switched and injection-seeded Nd:YAG laser ͑1064 nm, 10 ns pulses, 50 Hz͒ is used to pump the sample at the angle of incidence of 45°.…”

Nonlinear Optics and Chirality

“…The polymer is a poly(isocyanide) 30 functionalized with a nonlinear optical chromophore (see Figure 9.14). In this particular system the optical nonlinearity and chirality are present on two different levels of the molecular structure.…”