Preparation, Characterizations and Oxidation Stability of Polyethylene Coated Nanocrystalline VO₂ Particles and the Thermo-Chromic Performance of EVA/VO₂@PE Composite Film

Abstract

<jats:p>In this study, an alternative approach is presented for developing thermo-chromic film, based on ethylene vinyl acetate copolymer (EVA) and vanadium dioxide (VO<jats:sub>2</jats:sub>) composite, with enhanced oxidation stability and compatibility. The neat monoclinic nanocrystalline VO<jats:sub>2</jats:sub> particles were firstly prepared via a hydrothermal process, using citric acid as a reducing agent. After that, the synthesized VO<jats:sub>2</jats:sub> particles were characterized, prior to mixing with maleic anhydride grafted PE. The crystalline structure, morphology and thermochromic performance of the polyethylene coated vanadium dioxide (VO<jats:sub>2</jats:sub>@PE) particles were then verified by SEM, TEM, DSC, XRD, FTIR techniques. After coating, a better oxidation stability of the VO<jats:sub>2</jats:sub> particles was noted while the thermo-chromic performance of the VO<jats:sub>2</jats:sub>@PE was also maintained. After mixing with EVA, the percentage strain and tensile toughness of the VO<jats:sub>2</jats:sub>@PE based EVA films was the highest, followed by those of the uncoated VO<jats:sub>2</jats:sub>-based EVA films and the neat EVA, respectively. The VO<jats:sub>2</jats:sub>@PE-based films also maintained the thermochromic behavior of the monoclinic VO<jats:sub>2</jats:sub>. The above improvements were achieved at the expense of percentages of visible light transmittance and gel content of the EVA. This is the first report of the EVA/VO<jats:sub>2</jats:sub>-based thermo-chromic film, which is tougher and more stable toward oxidation than the prior state of the art. This composite film has the potential to be used as a kind of a specialty lamination material for smart windows and energy efficiency in buildings.</jats:p>

Preparation of VO2 Nanoparticles with Surface Functionalization for Thermochromic Application

“…The average diameter of VO2 particles is approximately 0.5 m with the coating thickness of 0.003-0.005 μm. This TEM image reveals the aggregation of core-shell structure of coated VO2 particles, similar to the results obtained previously by Tong et al [10], Chen et al [11] and Srirodpai et al [12]. In consideration of obtained thickness of APTES layer, the formation of multilayer [22] is also possible in addition of monolayer coating.…”

“…VO2 particles were prepared from reduction reaction of V2O5 by citric acid followed by hydrothermal and calcination process (Eq. (1)) [12]. 5 4.67 4.5 4.33 4 2 5 3 7 4 9 6 13 2…”

The effects of thermochromic pigments on optical, mechanical, and heat insulation properties of plasticized PVC window film

“…This could be related to the presence of hydroxy (OH) groups on the surface of the synthesized VO 2 particles. 23 In this regard, a polar interaction between OH groups of VO 2 and chlorine (Cl) atoms of the PVC molecules might contribute to a better compatibility and greater tensile properties of the composites.…”

EVA Film Reinforced with Acid Functionalized Graphene Nanoplatelets as a Transparent Barrier Layer to Enhance the Durability of Solar Cells

“…The swelling experiment was carried out for seven days. More details concerning the experimental procedures were described in our earlier report [21,22].…”