Controlled change of structure and properties of nanometer polymer layers deposited by electron beam polymerization from vapour phase

摘要

Electron beam polymerization of monomers from vapour phase is advanced method of thin polymer layers (TPL) deposition on solid substrates. The structure features and properties of TPL formed from tetrafluoroethylene and methylmethacrylate vapour at different E-beam current densities were found to be different strongly. In 1-10 μA/cm2 field the low molecular mass PTFE films with tape and disk supramolecular structures formed. These films are low thermostable (to 250-300) because of sublimation under heating. Macromolecules in these films are regulated (mesomorphic state). The polymer chain axes are oriented perpendicularly toward substrate surface. In 102-103 μA/cm2 field the films with high thermostability (400-450) form. These films are probably crosslinked. In 104-106 μA/cm2 field the amorphous, strongly crosslinked, high thermostable, high uniform films form. Polymethylmethacrylate (PMIMA) films formed at 1-10 μA/cm2 rapidly dissolve in organic solvents. The PMMA films deposited at 102-103 μA/cm2 only swell in organic solvents. The observed differences of structure and properties of films deposited by E-VDP method are caused probably by different balance of chain polymerization and polyrecombination mechanisms in the film deposition processes. In highest current density range the polyrecombination mechanism predominates. In low current density the main mechanism of deposition is the radical-chain polymerization. The results obtained show great possibilities of controlled change of properties of E-VDP films deposited from the same precursor.