Structural and Morphological Characterization of Ultrathin Films of an Asymmetric Polydiacetylene

Abstract

A soluble, asymmetrically substituted polydiacetylene, poly(BPOD), has been reported to form stable monolayers at the air-water interface by the Langmuir-Blodgett (LB) technique [2]. Preformed polydiacetylene has been deposited onto hydrophobic substrates as multilayers to form second order nonlinear optical thin films. Second harmonic generation was found to increase with the number of layers. From previous atomic force microscopy (AFM) studies backbone orientation along the dipping direction with an interchain spacing of about 5 A° was indicated [2].The film morphology and preferential molecular orientation of these LB films are further investigated by transmission electron microscopy (TEM). A specifically tailored sample preparation method for the ultrathin LB films was used. Multilayer films were deposited on hydrophobic collodion covered glass substrates for this purpose. Electron diffraction was employed to study the crystalline organization of mono and multilayers of LB films as well as cast films.

Novel Layer-by-layer Complexation Technique and Properties of the Fabricated Films

“…Emission characteristics of the samples were measured using a SLM-AMINCO Model 8100 spectrofluorometer from 500 to 700 nm. A sample for transmission electron microscopy (TEM, Philips EM 400T) was made on collodion film according to literature . Energy-dispersive X-ray spectrometry (EDXS, Tracor Northern TN5500) was used to obtain information on the elemental composition from the multilayer films.…”

“…A sample for transmission electron microscopy (TEM, Philips EM 400T) was made on collodion film according to literature. 28 Energy-dispersive X-ray spectrometry (EDXS, Tracor Northern TN5500) was used to obtain information on the elemental composition from the multilayer films. Thickness of the thin films was measured using atomic force microscopy (AFM, Park Scientific, SFM-BD2, and STM-SA1) and ellipsometry (Rudolph Research, Auto EL ellipsometer).…”