层层组装法制备(LDH/DNA/LDH/LTO)n多层复合膜及其红外辐射性能

Layer⁃by⁃Layer Assembly and Infrared Emissivity of(LDH/DNA/LDH/LTO)n Hybrid Films

采用层层自组装(LBL)的方式将带负电荷的层状氧化钛(LTO)纳米片以及DNA分子和带正电荷的层状双氢氧化物(LDH)纳米片交替组装,制备了一种人工设计的杂化薄膜,并研究了样品在8~14μm波段的红外发射率。X射线衍射(XRD)结果表明,(LDH/DNA/LDH/LTO)n杂化膜在垂直于基底的方向呈长程堆积的有序结构,DNA分子链和LTO纳米片均以单层的形式平铺在LDHs层板间。从扫描电子显微镜(SEM)和原子力显微镜(AFM)图像可以看出,薄膜呈现出均匀的、连续的表面形态。通过能量色散X射线光谱(EDS)和X射线光电子能谱(XPS)分析,确认了薄膜的组分,且每一种组分都均匀地平铺在每一个组装单层中,在垂直于基底的方向有序堆积形成均匀的薄膜。由于多组分之间存在协同作用,而且规整有序的层状薄膜结构的构筑增强了不同组分之间的界面效应、提供了平整光滑的薄膜表面,使该复合薄膜的红外发射率降低至0.419。这些结果清楚地表明,层层自组装方式制备的杂化复合膜能有效降低其红外发射率。

Herein,by using sequentially electrostatic layer-by-layer(LBL)deposition method,the artificialdesigned hybrid films were fabricated through the alternatively assemble of negatively charged layered titanium oxide(LTO)nanosheets and DNA molecules with positively charged layered double hydroxide(LDH)nanosheets.The infrared emissivity values at the wavelength of 8~14μm of the as-synthesized samples were investigated.The X-ray diffraction(XRD)results demonstrate that the(LDH/DNA/LDH/LTO)n hybrid films were orderly stacked on the substrate in the normal direction,in which the DNA molecules and LTO nanosheets were accommodated as monolayer between the LDH nanosheets layers,respectively.It can be seen from the scanning electron microscope(SEM)and atomic force microscope(AFM)images that the surface morphology of the film was uniform and continuous.The energy dispersive X-ray spectroscopy(EDS)and X-ray photoelectron spectroscopy(XPS)analysis verify the composition,the homogenous element distribution,and the well-ordered structure in the multilayer films.This multilayered hybrid film with tetra-layer units possessed a low infrared emissivity value of 0.419 based on the synergistic effect of its multi-components,the interfacial interaction between different layers and the uniform and smooth surface.These results clearly demonstrate that the ordered LBL assembly of the artificial designed hybrid film is quite effective in decreasing the infrared emissivity value.