Scalable synthesis of degradable copolymers containing α‑lipoic 2 acid via miniemulsion polymerization

A robust method is described to synthesize degradable copolymers under
aqueous miniemulsion conditions using α-lipoic acid as a cheap and
scalable building block. Simple formulations of α-lipoic acid (up to 10
mol%), n-butyl acrylate, surfactant, and costabilizer generate stable
micelles in water with particle sizes <200 nm. The ready
availability of these starting materials facilitated performing
polymerization reactions at large scales (4 L), yielding 600 g of
poly(n-butyl acrylate–stat–α-lipoic acid) latexes that degrade under
reducing conditions (250 kg mol–1 → 8 kg mol–1). Substitution of α-lipoic
acid with ethyl lipoate further improves the solubility of dithiolane in
n-butyl acrylate, resulting in copolymers that degrade to even lower
molecular weights after polymerization and reduction. In summary, this
simple and scalable strategy provides access to large quantities of
degradable copolymers and particles using cheap and commercially available
starting materials.