Jing Du,Yanfeng Gao,Zhang Chen,Litao Kang,Zongtao Zhang,Hongjie Luo
Application of VO 2 to smart windows calls for an enhancement of both luminous transmittance ( T lum ) and solar transmittance modulation (Δ T sol ). These two properties are related to optical constants , microstructure and film thickness. In this article, VO 2 -based films with increased microroughness are prepared by polymer assisted deposition , and ZnCl 2 is added to the precursor solution to control the microstructure of the films. Addition of ZnCl 2 increases the microroughness of films through phase separation, which largely decreases the refraction index and the reflectivity of the films, resulting in enhanced luminous transmittance and solar transmittance modulation; two films with balanced optical performance show T lum =50.5% and Δ T sol =11.3%, and T lum =59.3% and Δ T sol =10.5%, respectively. Moreover, this kind of microstructure control has no influence on doping VO 2 , which is proven by the deposition and characterization of W-doped VO 2 -based films. By the formation of a W-doped VO 2 /F:SnO 2 /glass multilayer stack, a film shows excellent thermochromic properties and low emissivities; typically, a film with a phase transition temperature, T lum , Δ T sol of 43.4 °C, 30.0%, 8.82%, respectively, and emissivity of 0.20 for monoclinic and 0.33 for rutile phase is successfully prepared.
Qiwen Yong,Bing Liao,Jianheng Huang,Ying Guo,Caizhen Liang,Hao Pang
A novel waterborne polyurethane (WPU) resin with low gloss and micro-roughness was synthesized by the prepolymer and self-emulsification method. It was achieved by introducing multi-hydroxyl castor oil and reactive bisphenol A-type epoxy E-44 or E-51 resin to polyurethane prepolymer to form a cross-linking network structural waterborne polyurethane emulsion, which demonstrated the distinctive characteristic of the shear-thinning pseudoplastic fluid with a yield stress. The chemical structures and rough surface morphologies of the WPU films were characterized by FTIR-ATR, LCRS , AFM , SPMS and SEM, respectively. The specular gloss values at 20°, 60° and 85° incident angles were measured, and the values of different kinds of roughness parameters were obtained. The relationship between the gloss and the castor oil content was also discussed in detail. In general, this WPU resin endowed the film with micro-roughness, moderate hardness and good adhesive strength , making it very prospective in substitution for the traditional low gloss coatings.
危险品化学品经营许可证（带存储）