Dielectric Response in the First Silicon Phthalocyanine Network Polymer Wael Darwish • Gamal Turky Received: 14 July 2013 / Accepted: 2 September 2013 / Published online: 26 September 2013 Ó Springer Science+Business Media New York 2013 Abstract Unlike the well known silicon phthalocyanine polymers, which are only bridged polymers, the first sili- con-phthalocyanine network polymer [PcSiCl 2 ] x 6 was prepared from commercially available precursors. Based on previous modeling studies, elemental composition allowed for determination of both the shape and the content of Pc units in the prepared polymer. The two-dimensional network structure was found to offer an extension of the conjugation of the 18-p electron system of the phthalocy- anine and facilitate the charge mobility across the material. This was found to enhance the conductivity and dielectric properties of the material, relative to the analogue materi- als, by supporting the hoping conduction mechanism. Differential scanning calorimetry was used to follow the non-oxidative thermal degradation of the prepared poly- meric material. An interesting phenomenon, water effu- sion, was detected and proved to play a role in the conduction mechanism. Electrical and dielectric measure- ments were carried out at different frequencies. The poly- mer has extremely high values of the permittivity e 0 and dielectric loss e 00 at lower frequencies that decrease grad- ually with increasing frequency. The relaxation peak at lower frequencies showed without doubt that the moisture enhances the conductivity. Keywords Conductivity  Dielectric permittivity  Polymers  Phthalocyanines  Silicon 1 Introduction Phthalocyanines (Pcs) are widely used in materials science as pigments, semiconductors, sensors, photodynamic reagents and non-linear optical materials [1, 2]. Polymeric Pcs were first discovered in 1950s as a new promising class of p-conjugated conductor polymers [3]. An important fea- ture of polymeric Pcs is their unique chemical structure with an extended conjugation even more than their low molecular weight Pcs, and therefore they are known as high-dielectric materials [4] and gas sensors [5]. Phthalocyanine polymers are generally prepared by polycyclotetramerization of (1,2,4,5-benzenetetracarboxylic dianhydride) or (1,2,4,5- benzenetetracarbonitrile) at high temperature [6, 7]. The reaction pathway is far more complex when benzenetetra- carboxylic acid derivatives instead of benzenetetracarbonit- rile derivatives are used as starting materials [8, 9]. Types of phthalocyanine polymers are: network polymers [10], bridged (shish-kebab) polymers [11], network-bridged polymers [12], ladder-polymers [13], and sheet-polymers [14, 15]. Despite the fact that network Pc polymers con- taining copper, cobalt, nickel, manganese, iron, and recently titanium [16] have been intensively studied, network Pc polymers containing silicon have not been yet reported. The only known silicon-phthalocyanine polymers are those of coordination type containing siloxane bridges [11, 17]. In this work we aimed at synthesis of the first silicon-phtha- locyanine network polymer and studying the factors Electronic supplementary material The online version of this article (doi:10.1007/s10904-013-9962-2) contains supplementary material, which is available to authorized users. W. Darwish (&) Department of Polymers and Pigments, National Research Centre, Elbohooth Street, Dokki, Giza 12622, Egypt e-mail: waeldarwish78@yahoo.com G. Turky Department of Microwave Physics and Dielectrics, National Research Centre, Elbohooth Street, Dokki, Giza 12622, Egypt e-mail: gamalturky@yahoo.com 123 J Inorg Organomet Polym (2014) 24:347–354 DOI 10.1007/s10904-013-9962-2