Langmuir-Blodgett films from lignins

The fabrication of Langmuir-Blodgett (LB) films from lignins is reported for the first time, Lignins extracted from Pinus caribaea hondurensis and sugar cane bagasse are shown to form stable Langmuir monolayers on ultrapure water which can be transferred onto glass' substrates in the form of Y-type LB films, The area per molecule increases linearly with the molecular weight of the bagasse lignins which were fractionated by GPC so that relatively monodisperse materials could be obtained. This contrasts with the results from the highly disperse Pinus lignins for which no clear trend in the change in area per molecule could be observed. Ellipsometric measurements indicated that the thickness of LB films from both types of lignin is 60 Angstrom per deposited layer, the films possessing a large free volume. This clearly demonstrates that lignin molecules assume a three-dimensional arrangement even within a single layer.