Clean synthesis of linear and star amphiphilic poly(ε-caprolactone)-block-poly(ethyl ethylene phosphonate) block copolymers: assessing self-assembly and surface activity. Issue 10 (5th May 2020)

• Record Type: Journal Article
• Authors: Baheti, Payal; Rheinberger, Timo; Gimello, Olinda; Bouilhac, Cécile; Wurm, Frederik R.; Lacroix-Desmazes, Patrick; Howdle, Steven M.
• Is Part Of: Green chemistry. Volume 22:Issue 10(2020)
• Page Start: 3248
• Page End: 3261
• Publication Date: 2020-05-05
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d0gc00819b
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Synthesis by ROP of star-like amphiphilic block copolymer surfactants composed of PCL hydrophobic segments and poly(phosphonate) as biodegradable segments. Abstract : Anionic ring-opening polymerization (AROP) of 2-ethyl-2-oxo-1, 3, 2-dioxaphospholane (EP) has been utilized to create alternative hydrophilic moieties for utilization in surfactants. The current "go-to" hydrophilic unit is poly(ethylene glycol) (PEG), but this is non-biodegradable and there is some evidence that its use can lead to accumulation of toxic by-products. We have created new approaches leading to water-dispersible, fully degradable amphiphilic block copolymers. Our approach utilized poly(ε-caprolactone)-based macroinitiators in a solvent free process with organocatalyst DBU. We have prepared a comprehensive set of novel amphiphilic PCL- b -PEP block copolymers including linear diblock, triblock and star diblock copolymers characterized by SEC, 1 H and 31 P NMR and MALDI-TOF analyses. Supercritical carbon dioxide (scCO2 ) was exploited to efficiently extract the residual EP monomer leading to significantly increased gravimetric yields of purified product compared to conventional techniques such as dialysis. The self-assembly of the amphiphilic copolymers in water was investigated by DLS and cryo-TEM and their surface-activity as a function of concentration was investigated by tensiometry showing behavior that matches or exceeds commercially available surfactants.