Hydroxypropyl β‐Cyclodextrin Solubilizing Hydrophobic Initiator to Initiate Copper‐Mediated RDRP of NIPAM in Aqueous Media. Issue 11 (19th March 2020)

• Record Type: Journal Article
• Authors: Lu, Hang; Gao, Ming; Song, Ronghao; Ye, Lin; Zhang, Ai‐Ying; Feng, Zeng‐Guo
• Is Part Of: ChemistrySelect. Volume 5:Issue 11(2020)
• Page Start: 3385
• Page End: 3390
• Publication Date: 2020-03-19
• Subjects: Cu0-RDRP -- HP-β-CD -- solubilize -- NIPAM; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202000269
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: The copper mediated reversible deactivation radical polymerization (Cu 0 ‐RDRP) can realize the precise synthesis of vinyl polymers in aqueous media. To our best of knowledge, there are few hydrophobic initiators directly utilized to perform the aqueous Cu 0 ‐RDRP because the heterogeneity usually causes the polymerization to go out of control. This article first describes a very small number of hydroxylpropyl β‐cyclodextrins (HP‐β‐CDs) enabling to solubilize a bifunctional hydrophobic initiator tetraethylene glycol bis(2‐bromoisobutyrate) (T2B) into water to initiate the homogeneous Cu 0 ‐RDRP of N‐isopropylacrylamide (NIPAM) giving rise to well‐defined poly(N‐isopropylacrylamide) (PNIPAM). The solubilization action is arisen from the inclusion complexation of HP‐β‐CDs with T2B as evidenced by 2D NOESY and 2D DOSY NMR analyses. Furthermore these entrapped HP‐β‐CDs show little effect on the polymerization process as they all skip off the initiator at the very beginning of the polymerization as determined by GPC and 1 H NMR measurements. Abstract : Hydroxylpropyl β‐cyclodextrins (HP‐β‐CDs) were used to solubilize a bifunctional water‐insoluble initiator T2B to initiate the aqueous copper mediated reversible deactivation radical polymerization (Cu 0 ‐RDRP) of N‐isopropylacrylamide (NIPAM). After the polymerization, HP‐β‐CDs can be easily removed by dialysis. The resulting polymers were featured by a controllable molecular weight, narrow monomodal molecular weight distribution and high chain‐end group fidelity.