Silicon-modified surfactants and wetting: I. Synthesis of the single components of Silwet L77 and their spreading performance on a low-energy solid surface

Defined surfactants of general formula [(CH3)3SiO]2CH3Si(CH2)3(OCH2CH2)3–9OCH3, have been synthesized from the corresponding oligoethylene glycol monoallyl monomethyl ethers via hydrosilylation. The concentration-dependent spreading performance on hydrophobized silicon wafers has been investigated and compared with that of Silwet L77. For the hexaethylene glycol derivative the highest initial spreading velocities and largest spreading areas were found. Since Silwet L77 spreads faster than all the other derivatives under investigation, a synergistic effect of different compounds is unlikely. Minor differences were found for handshaken and sonicated solutions.