The effect of formulation variables on fouling-release performance of stratified siloxane–polyurethane coatings

• Published in: Journal of Coatings Technology and Research Vol. 9; no. 3; pp. 235 - 249
• Main Authors: Bodkhe, Rajan B., Thompson, Stephanie E. M., Yehle, Carolyn, Cilz, Nicholas, Daniels, Justin, Stafslien, Shane J., Callow, Maureen E., Callow, James A., Webster, Dean C.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-05-2012
• Subjects: Chemistry and Materials Science; Corrosion and Coatings; Industrial Chemistry/Chemical Engineering; Materials Science; Polymer Sciences; Surfaces and Interfaces; Thin Films; Tribology; Marine coatings; Fouling; Siloxane; Polyurethane
• ISSN: 1547-0091; 1935-3804
• DOI: 10.1007/s11998-011-9362-x

The effects of formulation variables, such as type of polyol, solvent type and solvent content, and coating application method, on the surface properties of siloxane–polyurethane fouling-release coatings were explored. Fouling-release coatings allow the easy removal of marine organisms from a ship’s hull via the application of a shear force to the surface. Self-stratified siloxane–polyurethane coatings are a new approach to a tough fouling-release coating system. Combinatorial High Throughput Experimentation was employed to formulate and characterize 24 different siloxane–polyurethane coatings applied using drawdown and drop-casting methods. The resulting coatings were tested for surface energy using contact angle measurements. The fouling-release performance of the coatings was tested using a number of diverse marine organisms including bacteria (
Halomonas pacifica
and
Cytophaga lytica
), sporelings (young plants) of the green macroalga (
Ulva linza
), diatom ((microalga)
Navicula incerta
), and barnacle (
Amphibalanus amphitrite
)
.
The performance of the majority of the coatings was found to be better than the silicone standards, Intersleek
®
and Silastic
®
T2. An increase in solvent content in the formulations increased the surface roughness of the coatings. Coatings made with polycaprolactone polyol appeared to be somewhat rougher compared to coatings made with the acrylic polyol. The adhesion strength of sporelings of
Ulva
increased with an increase in solvent content and increase in surface roughness. The adhesion strengths of
Ulva
sporelings,
C. lytica,
and
N. incerta
were independent of application method (cast or drawdown) in contrast to
H. pacifica
adhesion
,
which was dependent on the application method.