Modifying Hydrophilic Properties of Polyurethane Acryl Paint Substrates by Atomic Layer Deposition and Self-Assembled Monolayers

Abstract: A process of atomic layer deposition combined with self assembled monolayers was used to investigate the possible modification of polyurethane paint surfaces. First, we used an ALD process to produce thin and uniform Al2O3 coatings of these surfaces at temperatures as low as 40 degrees. We then successfully achieved the addition of 16phosphonohexadecanoic acid SAMs to the Al2O3 coated paint samples. Al2O3 coatings reduced the contact angle of the PUR surfaces from 110 to 10 degrees, accompanied by an initial hydrophobicity which however was not stable. over time. Addition of SAMs on the Al2O3 induced a sustained reduction in their contact angles to 60 to 70 degrees, and aging of the samples revealed a further decrease to 25 to40 degrees. Testing of the Al2O3 16 PHA coating in a Weather OMeter revealed its durability even under harsh outdoor conditions. These experimental results show that by combining ALD with SAMs it is possible to produce durable coatings with modified hydrophilic or hydrophobic properties that are stable over time. The use of SAMs with different end groups may allow fine tuning of the coating wetting properties