Surface pattern formation in UV-curable coatings

Some UV-curable coatings display matte surfaces after cure if they have und ergone a certain period of leveling at a temperature above their glass tran sition temperature and the melting point of any crystalline co-reagents pre sent in the formation. The matte finish of these coatings is due to the pre sence of coherent surface wrinkles after cure, which are similar in appeara nce to those induced by differential thermal contraction, when a metal laye r is sputtered onto a rubbery or viscous substrate. However, the wrinkles i n the UV-cured coatings appear under isothermal conditions, and it is, ther efore, inferred that they are due To the dynamics of internal stresses indu ced by through-thickness variations in the extent of curing.