(104d) Development and Properties of Novel Photo-Cleavable Surfactants

Recently, we have reported a new cinnamic acid-type photo-cleavable surfactant, C4-C-N-PEG9 that experiences a photo-cleavage through UV-induced cyclization in aqueous solution, yielding a coumarin derivative and an aminated polyoxyethylene compound¹⁾. Here, we have studied the effects of C4-C-N-PEG9 on the photorheological behavior of viscoelastic wormlike micelles formed by aqueous mixture of nonionic surfactants, polyoxyethylene phytosterol ether (PhyEO₂₀) and tetraoxyethylene dodecyl ether (C₁₂EO₄). When C4-C-N-PEG9 is added to the viscous, non-Newtonian 4.9 wt% PhyEO₂₀/H₂O + 2.4 wt% C₁₂EO₄ fluid, a decrease in viscosity is observed, while upon UV irradiation C4-C-N-PEG9 added solution regains the viscosity. It increases by 200 times, suggesting a modulation in micellar shape and size. The UV-Vis spectroscopy and HPLC measurements confirm that the trans-C4-C-N-PEG9 with large head group and its photodecomposition to form less surface-active coumarin derivative and an aminated polyoxyethylene compound are responsible for different rheological behavior²⁾.

References  1) H. Sakai, et al., Journal of Colloid and Interface Science, 376, 160-164, (2012).  

2)  H. Sakai, et al.,  Langmuir,  Article ASAP, DOI: 10.1021/la4001939.