scholarly journals Diblock, Triblock and Cyclic Amphiphilic Copolymers with CO2 Switchability: Effects of Topology

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 984
Author(s):  
Yuting Jiang ◽  
Tong Zhang ◽  
Zheng Yi ◽  
Yixiu Han ◽  
Xin Su ◽  
...  

The combination of topology and CO2 switchability could provide new options for amphiphilic copolymers. Cyclic molecules supply novel topologies, and CO2 switching provides stimulus responsiveness. Cyclic poly(2–(diethylamino)ethyl methacrylate)–b–poly(ethylene oxide) and their corresponding block copolymers were prepared from poly(ethylene oxide) and 2–(diethylamino)ethyl methacrylate via atom transfer radical polymerization and Keck allylation with a Hoveyda–Grubbs catalyst. Changes in conductivity, surface activity, and hydrodynamic size were examined to illustrate the switchability of the produced amphiphilic copolymers upon contact with CO2 in the presence of water. The reversible emulsification and switchable viscosity behaviors of the copolymers were also demonstrated.

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Yang Runmiao ◽  
Shi Ronghua ◽  
Zhou Dan ◽  
Wang Yanmei ◽  
Han Yanchun

AbstractPoly(ethylene oxide)-b-poly(N, N-dimethylacrylamide) (PEO-b-PDMA) was synthesized by successive atom transfer radical polymerization (ATRP) of N,N-dimethylacrylamide (DMA) monomer using PEO-Br macro initiators as initiator, CuBr and 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazamacrocyclotetra decane (Me6[14]aneN4) as catalyst and ligand.PEO-Br macroinitiator was synthesized by esterification of PEO with 2-bromoisobutyryl bromide. GPC and 1H NMR studies show that the plot of ln([DMA]0/[DMA]) against the reaction time is linear, and the molecular weight of the resulting PDMA increased linearly with the conversion. Within 3 h, the polymerization can reach almost 60% of conversion. PEO-b-PDMA copolymer with low polydispersity index (Mw/Mn≈1.1) is obtained. Self-assembly of PEO-b-PDMA in selective solvents is also studied. It could self-assemble into micelles in methanol/acetone (1/10, v/v) solution. TEM analyses of the PEO-b- PDMA micelles with narrow size distribution revealed that their size and shape depend much on the copolymer composition.


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