Metal-containing Polyelectrolyte Based Advanced Nanocomposited Thin Film

The design and fabrication of molecular materials has received a lot of attention and dedication in the last decades. It has been demonstrated that the control and tuning of the electronic and/or photonic properties of such materials can be achieved by means of accurate synthesis of tailored molecules. However, a fundamental step towards the effective realization of molecular-based devices relies on the ordered placement of the active components into the nanoscale structure. In this thesis, self-assembly processes are gaining importance in the fabrication of such devices and thin-film or capsules thechnologies are considered to play a major role in future applications.Our research is focused on the synthesis of metal containg polyelectrolyte and development the intelligent thin film based on them. The thesis is divided into four parts.1. The molecular modules (ligands) which upon metal ion coordination (here Cobalt(II) is used ) result in metallosupramolecular coordination polyelectrolytes (CoMEPE's) with electronic properties are obtained. Then the (PSS/CoMEPE)40 films are synthesised by the layer-by-layer electrostatic assembly technique. Such multilayer thin films show the excellent electrochromic responses, i.e. reduction at–1.1 V results in a rapid increase of the absorbance (green colouration) whereas after stepping the potential back to 0.0 V the initial state (red colouration) is recovered. The response time is of the order of seconds in both colouration and"bleaching"processes. The optical contrast is visually noticeable and the optical density of the multilayer film is around 0.16. However, after several cycles a decrease in the absorbance of the film is noticed, which points to lost of material.2. In order to improve the cyclic life of the electromic film, we try to use other metal ions (Fe(II)) to coordinate with MEPE instead of Cobalt ions. The results do show the improvement of cyclic life. Futhermore, in order to reduce the tedious fabraction processes and enhance the phase constrast; we establish the three-component systems by incorporating TiO2 nanocrystals into the bilayer of PSS/CoMEPE to form a tough and sandwich structure. As compared to the films without the nanocrystal, the hybrid films show a 5-fold increases of the phase contrast and 10-times of the memberane thickness.3. In this part, a different metal containing polelectrolyte poly(ferrocenylsilane) (PFS) is designed and prepared. Redox-responsive poly(ferrocenylsilane) (PFS) polyanions and polycations, are successfully employed in the electrostatic layer-by-layer supramolecular self-assembly process to form fully free-standing organometallic microcapsules. Microcapsules were obtained by coating the same type of PFS multilayers on colloidal particles (manganese carbonate (MnCO3)) followed by core removal using ethylenediaminetetraacetic acid (EDTA). These capsules displaye desired stability and well-defined integrity. These stable capsules could serve as excellent candidates for the investigation of polyelectrolyte multilayer permeability control triggered by redox stimuli.4. we introduce a new method to prepare macroporous films, which are fabricated by DNA and strong polyelectrolyte based on LBL assembly method. Then we try to interpret this phenoment.and introduce a new method to prepare macroporous film.