Growth of optically active chiral inorganic films through DNA self-assembly and silica mineralisation.
The circularly polarized reflection of nature is due to their distinct azimuthally twisted or helical character in the nanostructure of the surface films. Although many chiral inorganic powders have been successfully synthesised, the artificial synthesis of chiral inorganic films is rare. Herein, we reported a facile synthetic route for the growth of monolayered chiral film on the quaternary ammonium-modified silicon substrate. The films grew on the substrate surface because of the strong electrostatic interaction between positively charged quaternary ammonium groups and negatively charged phosphate groups of DNA, with subsequent growth to right-handed, vertically aligned, impeller-like helical architectures with left-handed two-dimensional square p4mm-structured DNA chiral packing. The DNA-silica composite films exhibited strong optical activity at 295 nm and in the range of 400-800 nm, corresponding to DNA chiral packing (absorption) and to the helical blade in the impeller (scattering), respectively. Upon removal of DNA templates, the pure inorganic impeller-like helical morphology was maintained; consequently, the scattering-based optical response was blue-shifted approximately 200 nm as a result of a decrease in the effective average refractive index. The hierarchical structures were reflected from the surfaces by cross-polarised light, which confirmed that the films were strongly birefringent, with long-range anisotropy.
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Ben
B
Liu
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Lu
L
Han
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Yingying
Y
Duan
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Yunayuan
Y
Cao
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Ji
J
Feng
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Yuan
Y
Yao
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Shunai
S
Che
D004247:DNA / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
D000644:Quaternary Ammonium Compounds; D012822:Silicon Dioxide; D004247:DNA