In this study, a novel waterborne polyurethane (WPU) with azobenzene-containing (azo-containing) pendant groups was synthesized by isophorone diisocyanate, long-chain diol of polycaprolactone, 2-ethyl-2-methyl-butanoic acid (2,2-dimethylolpropionic acid), 10-(4-(phenyldiazenyl)phenoxy)decyl-3-hydroxy-2-(hydroxymethyl)-2-methylpropanoate, and N,N-diethyl-ethanamine (triethylamine). Moreover, the influence of ultraviolet and visible (UV-Vis) light irradiation on the viscoelasticity of azo-containing WPU film in terms of the reversible trans-cis photoisomerization of azo-containing pendant groups was investigated by UV-Vis light spectroscopy, atomic force microscopy, and dynamic thermomechanical analysis. The results revealed that the adhesion of azo-containing WPU with single crystal silicon atomic force microscope probe was about 13 nN when irradiated by 450 nm Vis light for 60 s at 25 °C. Subsequently, the adhesion increased to 82 nN after irradiation with 365 nm UV light for 60 s at 25 °C. In addition, the azo-containing WPU presented a photo-induced reversible transition of tensile modulus and tanδ in the range from about 2 MPa to 22 MPa and 6000 to 0.35 with UV-Vis light cyclic irradiation for 120 s at 25 °C, respectively.

在这项研究中，通过异佛尔酮二异氰酸酯，聚己内酯的长链二醇，2-乙基-2-甲基丁酸（2,2-羟甲基丙酸），10-（4-（苯基二氮烯基）苯氧基）癸基-3-羟基-2-（羟甲基）-2-甲基丙酸酯和N，N-二乙基乙胺（三乙胺）。此外，就可逆反式而言，紫外线和可见光（UV-Vis）辐照对含偶氮WPU膜的粘弹性的影响紫外光可见光谱，原子力显微镜和动态热力学分析研究了含偶氮侧基的光异构化。结果表明，在25°C下用450 nm Vis光照射60 s时，含偶氮的WPU与单晶硅原子力显微镜探针的附着力约为13 nN。随后，在25°C下用365 nm紫外线照射60 s后，粘附力增加至82 nN。此外，含偶氮基的WPU呈现拉伸模量和tanδ的光致可逆过渡δ在25℃下的范围为约2MPa至22兆帕和6000至0.35与120秒的UV-VIS光环状照射，分别。