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

Herein, by using sequentially electrostatic layer-by-layer (LBL) deposition method, the artificial-designed 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 similar to 14 mu m 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.