New approach to diagnostics of organic impurities in water

Interfacial Flows and Interfacial Shape Modulation Controlled by the Thermal Action of Light Energy

“…Later on, a research group [10][11][12][13][14][15][16][17][18][19][20] developed a new direction in photothermal spectroscopy of liquids [10][11][12][13][14][15] and non-destructive testing of solids [16][17][18][19][20] based on the effect of the laser-induced thermocapillary convection in thin liquid layers. Low volatile liquids (aromatic hydrocarbons, aromatic alcohols, silicone oils of different viscosity) on absorbing the laser beam (λ = 633 nm, P ≤ 20 mW) substrates were used in experiments.…”

“…where n is the power exponent decreasing with viscosity of these liquids. In [13,14], a lag time between the moment of the laser beam turning on and appearance of the PTC signal on a screen was detected. The quadratic dependence of the lag time on the thickness of liquid layer, τ d ≈ h 2 l /χ l was considered as a basis for a method of measuring the thermal diffusivity of non-absorbing irradiation pure liquids [13].…”

“…The effect of surfactant additives to pure liquid on the thermally induced Marangoni convection opens up the perspectives for the development of highly sensitive instruments for physicochemical analysis [14], the study of the surfactant films rheology [21,22,73] and solving problems in microfluidics [23,24].…”

“…The effect of the delay of the PTC signal from a thin layer of optically transparent water on the light-absorbing ebonite substrate was found to be very sensitive to presence of any organic impurities on water-air interface [14]. The authors shown that by adding to pure water layer of microdroplets of the solution of hexadecanol in chloroform, the deviation from the quadratic dependence of the delay time is observed.…”

“…Today, optical radiation (light) is widely used as a high-precision and efficient tool for controlling the fluid flow, the shape of the liquid-liquid or liquid-air interfaces, and manipulating small objects suspended in the bulk liquid phase or located on the interfaces. Using light makes it possible to solve a wide range of problems in various applications, including biological research [1][2][3][4], liquid diagnostics [5][6][7][8][9][10][11][12][13][14][15], non-destructive evaluation of solids [16][17][18][19][20], methods for studying properties of soft interfaces [21][22][23][24], electronic industry [25][26][27][28][29][30][31], technologies of tunable and biomimetic optics [8,[32][33][34], image recording systems [35][36][37][38], and non-linear optics [39,40].…”