A surfactant and a method of forming the surfactant having the formula (I) where a is an integer from 1 to 10, b is an integer from 0 to 10, R1 is —CH3 or —H, n is an integer from 0 to 20, and R2 is a moiety selected from the group consisting of (II), (III), (IV), (V), (VI), (VII) or (VIII) where m is an integer from 0 to 4. The surfactant can be used in a method for preparing a rigid polyurethane foam.