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11ВКВО-2021- НАНОФОТОНИКА
DOI 10.24412/2308-6920-2021-6-298
АКТИВНАЯ ТЕРМОПЛАЗМОНИКА ДЛЯ ДЕТЕКТИРОВАНИЯ СТЕКЛОВАНИЯ В НАНОРАЗМЕРНЫХ ПОЛИМЕРАХ
Черных Е.А.1, Шелаев А.В.1, Казарян С.Г.2
1Казанский Федеральный Университет г. Казань 2Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, United
Kingdom
Работа посвящена разработке метода спектроскопической диагностики стеклования в пространственно-ограниченных аморфных полимерах на основе тугоплавкой термоплазмоники и Раман термометрии
This work tells us about spectroscopic sensing of the glass transition temperature (T ) of spatially
g
confined PMMA polymers deposited on a plasmonic refractory metasurface using pump-controlled Raman thermometry [1]. The refractory metasurface design represents an array of square-shaped TiN pads on a c-Si (100) substrate, as shown in Fig. 1. The latter functions as a temperature-sensing Raman reporter. This
«thermometer» was thoroughly calibrated through both a temperature-dependent anti-Stokes/Stokes ratio and the Raman peak shift by utilizing a macroscopic resistive hot plate.
We have theoretically and experimentally investigated the optical heating of a TiN pad under cw laser illumination. FDTD/FEM simulation allows us to detect the temperature increase by 170 K using a 200x200x50 nm3 TiN pad. We have realized that optical heating can be tuned through extruding c-Si pillars beneath the TiN pad. The longer the c-Si pillar the larger net temperature is achieved. Under cw illumination, a typical 1/ r behavior of a temperature profile is changed by r~M (у < 1) that corresponds to a much less confined profile. This enables thicker polymer films to warm up or to reduce the thermal gradients. The spatial resolution in monitoring the Tg is defined by the lateral size
of the TiN pad. The obtained results pave a route for designing thermoplasmonic metasurfaces able to heat up a sample of interest non-uniformly. In particular, it enables one to create a system of distributed thermal sources generating heat of different magnitudes under the given cw laser illumination. It is important to emphasize that the optical heating is made within a single TiN pad only and, therefore, the rest of the specimen remains intact. Finally, this study will benefit the development of spatially resolved spectroscopic sensing methods for 2D mapping phase transitions of heterogeneous glassy polymers and liquid crystals, polymeric blends and 3D confined polymers
Acknowledgements
This work was supported by grant No. 19-12-00066 of the Russian Science Foundation. we acknowledge a technical support from our industrial partners: Ostec group, ScanSens and NT-MDT. This work was done using equipment of Federal Center of Shared Facilities of Kazan Federal University.
References
1. Kharintsev S.S., Chernykh E.A., Shelaev A. V., Kazarian S. G., Nanoscale Sensing Vitrification of 3D Confined Glassy Polymers Through Refractory Thermoplasmonics //ACSPhotonics 8, 5, 1477-1488 (2021)
Fig. 1. Sketch of a metasurface consisting of square-shaped TiN nanoantennas on a c-Si substrate for sensing the glass transition in a PMMA polymer
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