Self-Assembly of Supramolecular Gels in Complex Anti-icing Fluids to Create Multicomponent Materials with Enhanced Performance.

Low-molecular-weight gelators (LMWGs) based on 1,3:2,4-dibenzylidenesorbitol (DBS, DBS-OCH3 and DBS-SCH3) were formulated into anti-icing products (ABC 3, ABC K+, ABC S+) containing polymeric additives, creating hybrid gels. Gels formed at significantly lower concentrations than in the base solvent (monopropylene glycol:H2O, 50:50), suggesting that the LMWG and the polymer in the anti-icing fluid can cooperate to form a sample-spanning gel. More thermodynamically stable, stiffer gels assemble more rapidly in higher-performance anti-icing fluids (ABC S+ and ABC K+). This suggests that LMWG-polymer interactions in lower-performance fluids (ABC 3) may compete with the assembly of the LMWG, reducing its ability to form a sample-spanning network. TEM visualized nanoscale fibrillar networks for all LMWGs in these anti-icing fluids. In the case of the most hydrophobic gelator (DBS-SCH3), globular structures associated with the polymeric additive were attached to these gel fibers. This correlated with the fact that DBS-SCH3 gave the softest, least stable gels suggestive of interactions between the LMWG and the polymer. The LMWG-modified anti-icing fluids were tested as anti-icing agents and significant increases in "holdover time" were achieved. As expected based on our observations of gel assembly, these increases were least significant in ABC 3. Pleasingly, Type II anti-icing fluid ABC K+ could be improved to a high-performance Type IV fluid by the addition of very small amounts of these LMWGs (0.25 g/L). Aerodynamic testing indicated that the gels were broken down by strain. Given the low cost of these LMWGs, the ease of coformulation by simple mixing, and the significant enhancements in anti-icing performance, we suggest they may see application in this technology.