LAUSR

Abstract The gelation ability of a series of partially fluorinated N -benzoyl- N′ -aryl thiourea derivatives (BTUs) newly designed and synthesized was examined in six different alcohols (ethanol, 1-propanol, 2-propanol, 1-butanol, 1-octanol and 1-decanol). After a general assessment through the test-tube inversion method and polarizing optical light microscopy, the viscoelasticity of two different types of decanol-BTU systems ( 1a and 1b ) was investigated via dynamic rheology in the 15–70 °C temperature range and 0.25–100 Hz frequency domain. A complex different behavior was evidenced for each of these mixtures, mainly due to the completely different morphologies resulted during gel formation and clearly illustrated trough scanning electron microscopy (SEM), even though the structural difference between the two BTUs 1a and 1b is minor (longer alkyl chain for latter). To explain how the gelator molecules 1a and 1b self-assembly to gellify the decanol, a structural mechanism has been proposed relied on their rheological behavior, on one hand, and the findings revealed by differential scanning calorimetry (DSC), polarizing optical light microscopy (POM), infrared spectroscopy (FT-IR - ATR), powder X-ray scattering (XRD) and SEM, on the other hand.