Atomic and molecular layer deposition for surface modification

• ALD/MLD can be used to adjust surface characteristics of films and fiber materials.
• Hydrophobicity after few deposition cycles of Al2O3 due to e.g. complex formation.
• Same effect on cellulosic fabrics observed with low temperature deposited TiO2.
• Different film growth and oxidation potential with different precursors.
• Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt.

Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces.However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjet printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid.

Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. Figure optionsDownload as PowerPoint slide