Nicotine Carboxylate Insecticide Emulsions: Effect of the Fatty Acid Chain Length

The effect of fatty acid chain length on nicotine carboxylate insecticide emulsions has been studied
in terms of particle size, interfacial tension, nicotine encapsulation on emulsion droplets, and bioactivity.
The particle size of the nicotine emulsion and the interfacial tension at the nicotine carboxylate oil
phase (0.03 M)−Tween 80 aqueous phase (0.001 M) were affected in a similar way by the change
in the fatty acid chain length, which was correlated by the packing conformation of Tween 80 and
nicotine carboxylate molecules as obtained by AM1 theoretical calculations. The amount of
encapsulated nicotine inside the nicotine carboxylate emulsion droplets influenced the insecticide
bioactivity of nicotine; this relationship was explained in terms of the acid value of the different fatty
acids used to prepare the nicotine formulation.
Keywords: Nicotine carboxylate; Tween 80; fatty acids; acid value; insecticide; bioactivity; interfacial
packing conformation