PVDF Films with Optimized Porous Structure Using Non-Solvent Induced Phase Separation for Passive Radiative Cooling
Contemporary Trends and Innovations in Textile Industry, Belgrade, Sırbistan, 19 - 20 Eylül 2024, ss.235-241, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Belgrade
- Basıldığı Ülke: Sırbistan
- Sayfa Sayıları: ss.235-241
- Süleyman Demirel Üniversitesi Adresli: Evet
Özet
Today, as personal thermal management gains importance for both
increased comfort and energy saving advantages, body cooling through the
clothing 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 films
having porous structures with tailored optical structures to enhance UV-VIS-NIR
reflectivity were produced from polyvinylidene fluoride (PVDF), via non-solvent-induced
phase separation method using two solvents and water. The porous structure of
PVDF films was optimized by differing polymer (5 and 10wt. %), water concentrations
(3-10%) and drying conditions. Besides SEM analyses to determine the pore
characteristics, cooling performances were evaluated by a hotplate apparatus
combined with a halogen lamb as a sun simulator. Indirect emissivity
calculations were carried out from the IR camera images of the films heated at
the same temperature with a fabric whose temperature was measured with sensors. According to SEM images, PVDF films having 10
wt.% polymer and 3% water concentrations had the most porous structure. The emissivity
of the optimized PVDF film with a hierarchically porous structure was enhanced
to 96.6% with a temperature decrease of 1.06°C under a solar irradiance of 600
W·m–2 indicating a good potential for a further cooling structure as
a nanocomposite and coated fabric forms.