Synthetic Metals 162 (2012) 995–999 Contents lists available at SciVerse ScienceDirect Synthetic Metals journa l h o me page: www.elsevier.com/locate/synmet Spectroscopy and electrochemical characterization of Langmuir–Blodgett and physical vapor thin films of 29-membered diazocrown ether 1 with two n-octyl substituents Flávio M. Shimizu a , Marystela Ferreira b , Anna S. Skwierawska c , Jan F. Biernat c , José A. Giacometti a,∗ a Faculdade de Ciências e Tecnologia, UNESP – Univ Estadual Paulista, CP 266, 19060-900 Presidente Prudente, SP, Brazil b Universidade Federal de São Carlos, Campus de Sorocaba, CP 3031, 18043-970 Sorocaba, SP, Brazil c Gdansk University of Technology, Faculty of Chemistry, 80-952 Gdansk, Poland a r t i c l e i n f o Article history: Received 9 November 2011 Received in revised form 11 April 2012 Accepted 14 April 2012 Keywords: Azocrown ether Cyclic voltammetry Langmuir–Blodgett film PVD film UV–vis spectroscopy FTIR spectroscopy a b s t r a c t UV–vis and FTIR spectroscopy and electrochemistry studies were performed on Langmuir–Blodgett (LB) and on physical vapor deposition (PVD) films of 29-membered diazocrown ether with two n-octyl substituents. FTIR and UV–vis measurements showed that PVD and LB films have distinct bands and dissimilarities in their intensities. PVD and LB films on ITO electrodes were also used as electrodes in cyclic voltammetry. Voltammograms showed that PVD and LB films have a distinct response for ions K + , but only LB film has specific selectivity to K + ions. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Crown ether molecules are built of carbon, oxygen and hydro- gen atoms where the oxygen is coupled between two carbon atoms to form the crown ether ring. Such molecules may be synthesized with different crown size that leads to different physical and chem- ical properties. Furthermore, an azo group can be inserted along the crown ether ring or lateral groups could be attached to the crown thus forming a hybrid azocrown ether molecule. The use of azocrown ether films on substrates as complexing agents is attractive since they have a strong ability to bind to certain cations forming bonds as a result of electrostatic forces. Thin films may be fabricated using several techniques, such as Langmuir–Blodgett (LB) [1,2], layer-by-layer (LBL) [3,4] and physi- cal vapor deposition (PVD) [5]. Nanostructured ultrathin films may be achieved with LB and LBL techniques to control their thick- ness [1,2]. The LB technique is preferable when the organization of molecules in the film is necessary to affect positively optical and electrical properties. As reported by Taunaumang and Tjia [5] for disperse red-1, the PVD technique is an attractive technique for highly oriented thin film fabrication. ∗ Corresponding author. E-mail address: giacometti@fct.unesp.br (J.A. Giacometti). Several azo- and azoxy-crown ethers have been synthesized and exhaustively studied by Biernat and co-workers [6–8]. But, so far there have been a few reports on the fabrication and char- acterization of thin films from azocrown ether derivatives [9,10]. Goldenberg et al. [6] reported on the electro- and photochemi- cal isomerization of 13-membered azocrowns in solutions and in LB films. Zawisza et al. [9] reported a detailed study using cyclic voltammetry of azocrown ethers LB films to recognize the iso- mers. Study of photoactivity isomers properties in Langmuir films at air–water interface were carried out by the Möbius group [11,12]. More recently, we fabricated Langmuir–Blodgett films from 29- diazocrown ether with two n-octyl substituents and showed that LB films display photoinduced birefringence [13]. The PVD technique is appropriate for small molecules and has attracted little attention since it requires that molecules be heated during film deposition. On the other hand, it is a straightforward technique, allowing the film thickness to be controlled with accu- racy. At our knowledge, there are also few reports on PVD films made from azobenzene materials: one describing the electro-optic activity [5], and the other characterizing the surface morphology [14]. This article reports on the fabrication of the PVD thin film of 29- diazocrown ether 1 with two n-octyl substituents. PVD and LB thin films were deposited on ITO electrodes were characterized using UV–vis and FTIR techniques and used as electrochemical sensors to 0379-6779/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.synthmet.2012.04.021