The influence of side chain length and sulfonyl moiety on the molecular structures and wettability behavior of poly(oxyethylene)s with alkyl sulfonyl side chains (CH3-nSE, n = 1, 2, 3, 4, 5, 6, 8, 10), where n is the number of the carbon atom in the n-alkyl side group, was investigated. CH3-nSEs having shorter side chains (n < 5) do not have ordered structures, and their surfaces were found to be more polar than those of CH3-nSEs having longer side chains (n 5). The CH3-nSEs having longer side chains show double-layered lamellar structures (n 5) with well-aligned side chains and low surface energies in the range 21.2-25.8 mN/m. Interestingly, stick-slip behavior was observed only on the surfaces of CH3-3SE and CH3-4SE when water was used as the test liquid. The surface deformation at the three-phase line was generated from interactions between water and sulfonyl groups, and the optimum side chain lengths were believed to cause the stick-slip behavior.