Micro- and nanostructured composite films for passive radiative cooling in ındoor environments
ICONST-International Conferences on Science and Technology, Budapest, Macaristan, 28 - 30 Mayıs 2025, ss.124-131, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Budapest
- Basıldığı Ülke: Macaristan
- Sayfa Sayıları: ss.124-131
- Süleyman Demirel Üniversitesi Adresli: Evet
Özet
Global
warming and energy crises have intensified attention in passive cooling
technology materials having self-cooling effect with zero energy consumption
and low carbon emission as a sustainable solution in recent years. In indoor
environment scenarios without sun, developing spectrally selective material
with tunable mid-infrared emissivity within atmospheric windows is crucial for
passive radiative cooling performance. Hierarchical porous polymer films
prepared by phase separation having pores with several micrometers size exhibit
strong mid-infrared scattering hence emissivity. Porous structure, pore size,
and also mid-infrared emissivity hence cooling performance of the polymer films
could regulate by selecting suitable polymer type, adding micro/nanoparticles,
adjusting the ratio of polymer/particles, and controlling phase separation
method parameters. Here, micro-nano porous nanocomposite films with randomly
distributed nanoparticles are fabricated through non-solvent induced phase
separation method, employing polyvinylidene fluoride (PVDF) and zinc oxide
(ZnO) nanoparticles (30 nm) at varying content (5-20% compared to polymer
content). Porous structure and cooling performance of the nanocomposite films
were evaluated by SEM and self-made hotplate system, respectively. To
understand the role of material and nanoparticle content on infrared radiation
emission and reflection, spectral reflectance and transmittance of the films in
the atmospheric window wavelength ranges were characterized using an FT-IR spectrometer
interfaced with integrating spheres in the diffuse reflectance mode.
Nanoparticles embedded in the polymer matrix especially at higher content led
to macro and nano-micro heterogeneous porous structure. The nanocomposite films
having 20% nanoparticle content selectively average atmospheric window
emissivity of 86%, enabling an average temperature drop of 1.97°C and 1.65°C
hence passive cooling performance in indoor environment scenario respectively,
compared with nonporous and porous PVDF film without ZnO particle. This cooling
performance could result in cooling-energy-consumption savings about
approximately 20% in indoor conditions, indicating high potential as a
sustainable material in a wide range of fields, from personal thermal management
textiles to energy-saving elements in a simple, cost-effective, and scalable
manner.