Morphological Properties of Hyperbranched Compound Containing Pyrrole Units
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Morphological Properties of Hyperbranched Compound Containing Pyrrole Units Lioudmila Fomina1, Jorge Godínez Sánchez1, José A. Olivares2, Fabio L. Cuppo Sant´Anna2, Luis E. Sansores1 and Roberto Salcedo1 1
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n. C.U. A. Postal 70-360. Delegación Coyoacán. C.P. 04510. México D.F., México. 2
Centro de Investigación en Polímeros, COMEX, Marcos Achar Lobaton No 2 Tepexpan, 55885, México. ABSTRACT Hyperbranched structures containing pyrrole units were obtained from ortho-, meta- and para-diaminodiphenyldiacetylenes as AB2 type monomers by one-step polymerization. The para-hyperbranched compound was observed by optical microscopy and scanning electron microscopy. Microscopy studies identify two phases. The first is the insoluble one which gives origin to flake type structures. The second is acetone soluble phase, which generated crystalline structure manifesting in optic anisotropy and rhomboids and triangles dendrimeric structures. INTRODUCTION In the last decades have been made several researches about the synthesis and characterization of many organic materials bearing highly conjugated structures. These materials exhibit semiconduction and non-linear optics properties, so that these compounds are used to elaborate electrochemical devices, organic light emitting diodes (OLEDs), rechargeable batteries, smart windows, among others. The dendrimeric polymers can be classified into three large groups [1]: a). The first one refers specifically to the basic dendrimers i.e. molecules which grow in branches [2] and they are prepared by in steps; b). The second group is formed by the so called dendro-injerted polymers [3] which have been described as the intermediated species between the dendrimers and the hyperbranched polymers; c). And the third group is constituted by the hyperbranched polymers [4, 5]. There are several species which belong to the third group [6]. They are very interesting substances with highly branched structures, third dimensional architecture, globular shape, terminal functional groups and particular electronic behavior [5]; they can be prepared by polymeric one or several steps synthesis [6]. The diacetylene derivatives shown in this communication belong to the third group. This work belongs to a research in which our group has published some interesting results [7, 8]. The new compounds can take orientations ortho-, meta- and para-. The para-hyperbranched compound was observed by optical microscopy and scanning electron microscopy. EXPERIMENTAL DETAILS Microscopy Analysis The para-hyperbranched sample was observed by optical microscopy and scanning electron microscopy. Since the sample is partially soluble in acetone, two different samples were
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prepared. The first sample was a mixture of powder with deionized water (0.1 % wt) and dispersed by 15 minutes in an ultrasonic bath. The second sample was prepared by mixing the powder sample in acetone to study the dissolved part of the para-hyperbranc
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