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Publikācija: Electro-Optics of TiO2 Nanowire Dispersions in PDMS Matrix

Publication Type Conference paper
Funding for basic activity Unknown
Defending: ,
Publication language English (en)
Title in original language Electro-Optics of TiO2 Nanowire Dispersions in PDMS Matrix
Field of research 2. Engineering and technology
Sub-field of research 2.5 Materials engineering
Authors Andris Šutka
Martin Timusk
Kristjan Saal
Vambola Kisand
Rünno Lõhmus
Keywords TiO2 nanofibers, electrospinning, Smart window, PDMS, suspensions
Abstract Low-cost electro-optical devices with fast, highly controllable and simple operation mechanisms, as well as long term stability are highly desirable for future generations of smart window technologies. There are different types of smart window technologies, for example thermochromics, photochromics, electrochromics, gaschromics, reflective metal hydrides, polymer-dispersed liquid crystals, gel-glass dispersed liquid crystal and dipole particle suspension (DPS) (also called suspended particle devices). From these solutions, the DPS devices allow great control of the transmittance of solar radiation and are also relatively simple. Here we report electro-optical properties of electrospun anatase TiO2 nanowire dispersions in polydimethylsiloxane (PDMS). It was found that changes in optical properties during TiO2 nanowire orientation in PDMS under the influence of an electric field are strongly influenced by nanowire (NW) diameter. It was found for the first time that either positive or negative change in transmittance can be induced by NW alignment parallel to the electric field depending on the NW diameter. Reported experimental findings could be important for smart window applications for the regulation of visible or even infrared transparency. In addition concentrations used in this study were 200 times lower than previously reported for titanium-based DPS devices, because the change in transmittance is attributed to a decrease of light scattering not absorption cross-section during the nanowire orientation along the direction of the electric field. The measurements of the influence of nanowire concentration and electric field strength on the nanowire orientation kinetics show that the device can be operated using electric fields as low as 0.1 V/μm and the magnitude of the change in transmittance can be adjusted by varying the TiO2 nanowire concentration in the PDMS matrix. A transmittance change of 23% was obtained with a DPS device using a suspension of 0.05 wt% electrospun anatase TiO2 in PDMS.
Reference Šutka, A., Timusk, M., Saal, K., Kisand, V., Lõhmus, R. Electro-Optics of TiO2 Nanowire Dispersions in PDMS Matrix. In: Fourth International Conference on Multifunctional, Hybrid and Nanomaterials: Thesis, Spain, Sitges, 9-13 March, 2015. Sitges: 2015, pp.P1.131-P1.131.
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