Description:
<p class="MsoNormal" style="text-align:justify;mso-layout-grid-align:none;text-autospace:none"><span lang="EN-US" style="font-size: 10pt;">Today, as personal thermal management gains importance for bothincreased comfort and energy saving advantages, body cooling through theclothing system by using natural energies has come to the fore. In this study,as the first step of a cooling garment design project, radiative cooling filmshaving porous structures with tailored optical structures to enhance UV-VIS-NIRreflectivity were produced from polyvinylidene fluoride (PVDF), via non-solvent-inducedphase separation method using two solvents and water. The porous structure ofPVDF films was optimized by differing polymer (5 and 10wt. %), water concentrations(3-10%) and drying conditions. Besides SEM analyses to determine the porecharacteristics, cooling performances were evaluated by a hotplate apparatuscombined with a halogen lamb as a sun simulator. Indirect emissivitycalculations were carried out from the IR camera images of the films heated atthe same temperature with a fabric whose temperature was measured with <a name="_Hlk164690297" style="">sensors. </a>According to SEM images, PVDF films having 10wt.% polymer and 3% water concentrations had the most porous structure. The emissivityof the optimized PVDF film with a hierarchically porous structure was enhancedto 96.6% with a temperature decrease of 1.06°C under a solar irradiance of 600W·m<sup style="">–2</sup> indicating a good potential for a further cooling structure asa nanocomposite and coated fabric forms. <i><o:p></o:p></i></span></p>