Synthesis and Characterization of Furan-Based Non-Ionic Surfactants (fbnios)

Two series of furan-based non-ionic surfactants (fbnios) were prepared by a combination of Williamson ether synthesis and anionic polymerization of ethylene oxide (EO). The reaction of 1-bromooctane and 1-bromododecane with 2,5-bis(hydroxymethyl)furan after deprotonation with potassium tert-butoxide yielded the corresponding alkane furfuryl alcohols (C-F-OH with x = 8 or 12). Deprotonation of C-F-OH with potassium tert-pentoxide enabled the anionic polymerization of EO, which yielded four C₈-F-EO samples with y = 3, 6, 9, and 14 and four C₁₂-F-EO samples with y = 9, 12, 18, and 23. The chemical composition of the fbnios was determined by NMR and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-ToF MS) analysis, while their dispersity (Đ) was characterized by gel permeation chromatography (GPC) and MALDI-ToF MS. The purity of the C-F-EO samples exceeded 92%, and they were produced with narrow molecular weight distributions (Đ ≤ 1.02, as determined by GPC analysis). The critical micelle concentration (CMC) of the C-F-EO samples was determined by surface tension and pyrene fluorescence measurements. These showed that the CMC of the fbnios could be tuned by adjusting the molecular parameters x and y, with the CMC increasing for decreasing x and increasing y. In particular, the CMC of the C₈-F-EO and C₁₂-F-EO samples was significantly higher and lower, respectively, than for typical non-ionic surfactants (nios) like the Triton X and Brij surfactant families. The efficiency, effectiveness, and cross section of the EO headgroup of the fbnios were also determined. Together, the CMC, efficiency, and effectiveness of the fbnios demonstrate that this new surfactant family displays tensioactive properties that match and even exceed those of traditional nios, suggesting that they could extend further the already broad range of applications for nios.