| 초록 |
Using in-situ X-ray/neutron reflectivity measurements, conformations of two dimensional polymeric chains has been measured as a function of MW and also surface pressure, Pi at air/water interface. Atactic hydrogenated and deuterated Poly (methyl methacrylate) (PMMA) were used in this study. Substantially onset area where Pi starts to increase in Pi-area isotherm can be recognized as a 2D territory of the chain, from which radius of gyration, Rg of two dimensional PMMA chain has been extracted. Rg scales as Rg~N^0.5, indicating that water behaves as a theta solvent for PMMA monolayer, which is consistent with the condition of theta solvent expected from mean-field calculation of Flory. At low pressure, thickness of the PMMA monolayer was shown to 0.9 nm and became double at high pressure. Further we analyze thickness and density of PMMA monolayer as a function of Pi. This result would be useful for nonopatterning via self-assembly of polymers where long-range ordering is important. |
