Langmuir‐Blodgett mono‐ and multilayers of preformed poly(octadecyl methacrylate)s, 1. Surface‐area isotherms of atactic and isotactic poly(octadecyl methacrylate)s and transfer into multilayers

In order to elucidate some of the parameters controlling the transfer of compressed monomolecular layers of preformed poly(octadecyl methacrylate)s (PODMA) onto substrates by the so‐called Langmuir‐Blodgett technique, an investigation was undertaken of PODMA's of different tacticity and different molecular weights. For the preparation of multilayered structures it was necessary to decrease the interaction between the side chains. This could be accomplished by introducing side chain inhomogeneities especially in the form of comonomers with shorter alkyl side chains. The transferability of a monolayer could be correlated with features in the pressure‐area diagrams, as there is a liquid‐analogous state formed when shorter alkyl chains are introduced; moreover a partial “melting” with lowering of the collaps pressure of the layer is seen. It appeared that with isotactic PODMA regular Y‐type transfer Y‐Type transfer: During one dipping and withdrawing cycle, two layers are transferred. Z‐Type transfer: Only during withdrawing one layer is transferred. took place, whereas with the atactic polymers at the beginning a Z‐type transfer occurred , gradually changing into a Y‐type transfer. Applying the concept of decreasing interaction of the side chains it was possible to prepare multilayers of isotactic and atactic PODMA's.