Photothermal Study of Two Different Nanofluids Containing SiO2 and TiO2 Semiconductor Nanoparticles

Abstract

Thermal and optical properties of two different nanofluids containing SiO 2 and TiO 2 semiconductor nanoparticles were studied by thermal lens spectrometry (TLS) and spectrophotometry. In the case of SiO 2 nanofluids the transmission electron microscopy technique was used to obtain the SiO 2 nanoparticle sizes to investigate the size effect of these nanoparticles on the sample thermal diffusivity which is important in some medical applications such as photothermal-modulated drug delivery systems. On the other hand for the case of TiO 2 nanofluids, the photopyroelectric technique, TLS, scanning electron microscopy, and X-ray diffraction were employed to investigate the concentration effect on the thermal properties of these nanofluids. Thermal diffusivities and effusivities as functions of the TiO 2 nanoparticle concentrations were obtained. From the experimental results, an incremental increase in the thermal diffusivities and effusivities was observed when the nanoparticle concentration was increased, indicating that the nanoparticle concentration is an important factor to be considered to obtain nanofluids with more thermal efficiency which are required for some applications, such as degradation of residual water.

Approach to the Assessment of Size-Dependent Thermal Properties of Disperse Solutions: Time-Resolved Photothermal Lensing of Aqueous Pristine Fullerenes C60 and C70

“…0.01% (for 10 –5 mol L –1 ) to 0.005% (for 10 –6 mol L –1 ). These values are in accordance with the same effect previously observed for nanoparticles and proteins. − The average distance between cluster centers in the AFDs of 10 –6 –10 –5 mol L –1 is calculated as 2–3 μm or 30–100 equivalent diameters.…”

The effect of nanoparticle size on thermal diffusivity of gold nano-fluid measured using thermal lens technique

“…(1) agrees very well with experimental data, which give the thermal diffusivity value for the sample as 2.510 ×10 −3 cm 2 /s. Thus by plotting the thermal diffusivity value as a function of nanoparticles sizes it shows the thermal diffusivity of the sample increases with the increasing of particle sizes [25]. This behavior is displayed in Figure 5 and agrees with the reasons highlighted by previous researchers such as, when the dimensions of particles become in order of phonon mean free path, phonon scattering effect become smaller as a result increase the thermal diffusivity [26].…”

Structural, optical, opto-thermal and thermal properties of ZnS–PVA nanofluids synthesized through a radiolytic approach

“…The interest in measuring the thermal conductivity ( k ) and the thermal effusivity ( e ) of nanofluids containing semiconductors has increased [ 15 ] because of their increasing use in devices [ 16 ]. The photoacoustic (PA) effect has been demonstrated to be a valid technique for these measurements.…”