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Acid‐Labile Amphiphilic PEO‐ b ‐PPO‐ b ‐PEO Copolymers: Degradable Poloxamer Analogs
Author(s) -
Worm Matthias,
Kang Biao,
Dingels Carsten,
Wurm Frederik R.,
Frey Holger
Publication year - 2016
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201600080
Subject(s) - copolymer , ethylene oxide , poloxamer , polymer chemistry , dynamic light scattering , amphiphile , miniemulsion , propylene oxide , materials science , polymerization , micelle , critical micelle concentration , acetal , ethylene glycol , nanoparticle , chemistry , aqueous solution , organic chemistry , polymer , nanotechnology
Poly ((ethylene oxide)‐ b ‐(propylene oxide)‐ b ‐(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid‐labile acetal moieties in the backbone of poloxamers to generate acid‐cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate‐protected vinyl ether to introduce acetal units. Three cleavable PEO‐PPO‐PEO triblock copolymers ( M n,total = 6600, 8000, 9150 g·mol −1 ; M n,PEO = 2200, 3600, 4750 g·mol −1 ) have been synthesized using anionic ring‐opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions ( Ð = 1.06–1.08). Surface tension measurements reveal surface‐active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid‐triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation “on demand.”