Selective Crystallization of d-Mannitol Polymorphs Using Surfactant Self-Assembly

Area of Science:

• Materials Science
• Chemical Engineering
• Crystallography

Background:

• Selective crystallization of polymorphs is critical for industrial applications, particularly in pharmaceuticals.
• Current methods often rely on complex engineered surfaces or pre-prepared heteronucleants, posing significant challenges.

Purpose of the Study:

• To introduce a novel, facile approach for controlling polymorphic outcomes using self-assembling surfactant structures.
• To demonstrate the potential of tailored surfactant self-assemblies as templates for crystal engineering.

Main Methods:

• Utilized sodium dodecyl sulfate (SDS) as a surfactant additive in solution.
• Investigated the self-assembly of SDS into various mesoscopic structures (monolayers, micelles, crystals).
• Examined the templating effect of these SDS mesophases on the crystallization of d-mannitol polymorphs (β, α, δ).

Main Results:

• Different SDS mesoscopic phases selectively directed the crystallization of specific d-mannitol polymorphs.
• Packed monolayers, micelles, and SDS crystals favored the formation of β, α, and δ d-mannitol, respectively.
• Evidence suggests a synergistic mechanism involving topological templating and molecular interactions.

Conclusions:

• Surfactant self-assemblies can serve as effective, readily prepared templates for controlling polymorphism.
• This crystal engineering technique offers a simplified and versatile strategy for achieving desired polymorphs in industrial settings.