Synthesis and Physicochemical Properties of Silicon-Terminated Octyl/Decyl Polyethylene Oxide as Novel Low-Foam Penetrating Agents

Low-foam penetrating agents have been sought after for many industrial applications. In this paper, we were aiming at a low-foam penetrating agent with excellent wetting ability and hydrolysis resistance, various silicon-terminated penetrating agents were designed and synthesized starting from a popular commercial penetrating agent, octyl/decyl polyethylene oxide (OEO). All the products present much better low-foam performances than that of the precursor OEO. Statistically, multi-OEO substituted products present the best low-foam performance but a slightly weaker wetting ability. Except octyl/decyl polyethylene oxide trimethyl silicane, all the other five products maintain excellent wetting ability and show good hydrolysis resistance at neutral pH and ambient temperature. Di(octyl/decyl polyethylene oxide) dimethyl silicane is the preferred low-foam penetrating agent based on its structure–performance and cost, which reduced the foam volume of OEO from 75 to 4 mL (on the 100 mL volume base) at neutral pH and ambient temperature with a similar wetting ability.