Alternate Langmuir-Blodgett Film Deposition with Polymer Nanosheets for Second Harmonic Generation
Miki Ishifuji, Masaya Mitsuishi and Tokuji Miyashita
The paper focuses on preparation of hetero-structured polymer nanosheets for second harmonic generation. The alternate layer structure was achieved by interleaving an NLO active azo dye copolymer (p(DDA/DR1), 18 mol% dye content) monolayer with a passive spacer, poly(N-dodecylacrylamide) (pDDA) monolayer. A novel Langmuir-Blodgett trough, which has a substrate holder both above and below the water surface, allowed alternate LB film deposition in which p(DDA/DR1) and pDDA nanosheets were alternately deposited by moving two compartments back and forth to the deposition area. The second harmonic light interference pattern was clearly obtained, indicating that the hetero-structured polymer nanosheets have highly oriented and well ordered non-centrosymmetric layer structure.