Growth of thin Al_2O_3 films on biaxially oriented polymer films by atomic layer deposition

摘要

The effects of thin film nucleation and initial growth on roughness, chemistry and thermomechanical properties of polymer film surfaces were studied. Al_2O_3 was deposited onto commercial biaxially oriented polypropylene and polylactic acid films at 80 ℃ by using atomic layer deposition technique. Both substrates, especially the more hydrophobic polypropylene, showed initial growth through Al_2O_3 clusters. There was a faster deposition of Al_2O_3 on polylactic acid film than on polypropylene at the early stages of the Al_2O_3 deposition. There were also indications of chemical interactions between polylactic acid and trimethyl aluminum used as a precursor for Al_2O_3. Changes in the thermo-mechanical properties of the polymer surfaces with Al_2O_3 also evidenced the differences between the substrate polymer films. The near surface interphase formed in polylactic acid probably contributed to the strong increase and scattering in the softening temperature during the early thin film growth.