Electrochromic properties of spiropyran-terthiophene adaptive polymers

Abstract

Adaptive materials have the ability to modify their behaviour or characteristics in response to external stimuli, for example through electrochemical changes, macroscopically in the molecular structure. These materials may have only one form with binding skills whilst others are passive. In principle this material can be switched ‘on’ and ‘off’ using external stimuli [3]. In this field hybrid Polythiophenes substituted with Spiropyrans are an important representative class of conjugated polymers that form environmentally and thermally stable materials and stimulate deep interest for their optoelectronic and reversible properties. An enhancement in the electronic and photonic properties of the materials and the creation of new functions, such as new sensory materials or new biocompatible structures, critically depends on the synthesis of polythiophene [1,4]. This problem can be bypassed with some synthetically procedures that have been developed by our group and published on previous outputs. In this work the new family of hybrid spiropyran-terthiophenes moieties has been fully characterized and analyzed. An important aspect emerged in the study consists is the charge transfer during the processes of activation and deactivation of the material [2]. It has been observed spectroelectrochemically that a consistent charge transfer occurs while the activated surface is stimulated with an external potential. The kinetics of activation and deactivation has been detected at different potentials. This plays a remarkable role in the complete description of the properties of the structure under different conditions, especially during the electrochemical activation of the material in an electrolytical cell. This offers the possibility of inducing dramatic changes to the bulk properties of the active system by electrochemical stimulus. Herein we present the electrochemical and spectrelectrochemical behaviour of our materials. BIBLIOGRAPHY 1. S. Gambhir, K. Wagner, D. L. Officer, Towards functionalised terthiophene-based polymers. Synthetic Metals 154, 2005: 117-120. 2. S. Hammes-Schiffer, A. V.Soudakov. Proton-coupled electron transfer in solution, Proteins and electrochemistry. Journal of Physical Chemistry B, 2008, 14108-14123. 3. A. Radu, S. Scarmagnani, R. Byrne, C. Slater, K. T. Lau, D. Diamond, Photonic modulation of surface properties: a novel concept in chemical sensing. Journal of Physics D: Applied Physics, 40, 2007, 7238-7244. 4. H. Mehenni, L. H. Dao, Synthesis and characterization of novel conducting homopolymers based on β-styryl terthiophene. Canadian Journal of Chemistry, 86, 2008, 1010-1018