A CO₂- and temperature-switchable “schizophrenic” block copolymer: from vesicles to micelles

Abstract

CO2-responsiveness is imported into amphiphilic block copolymers, poly[(N,N-diethylaminoethyl methacrylate)-b-(N-isopropylacrylamide)] (PDEAEMA-b-PNIPAM), and a system dual-responsive to CO2 and temperature is constructed. The copolymer self-assembles in aqueous solution, and undergoes phase transition when CO2 and temperature stimuli occur, since the stimuli give rise to the conversion of the hydrophilicity of both blocks. Combining CO2 and temperature as triggers, schizophrenic micelle to vesicle morphological transition of the polymer assemblies is controlled.

CO2-responsive polymeric materials: synthesis, self-assembly, and functional applications

“…28 For the preparation of the first block RAFT polymerization of DEAEMA was performed using 2,2-azobis (isobutyronitrile) (AIBN) initiator and 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid (DMP) RAFT agent at a molar ratio of 1 : 10. A dual CO 2 -and temperature-responsive block copolymer, PDEAEMA-b-PNIPAM, was synthesized with RAFT polymerization.…”

“…2 However CO 2 , which is a benign, inexpensive, abundant, and non-toxic trigger for stimuli-responsive materials, has received increasing attention in recent years. 5,6 Due to the very interesting properties of CO 2 as a trigger, CO 2 -responsive polymers have found potential applications in different areas including latexes, 7-13 gels, 14-17 CO 2 capturing and monitoring, [18][19][20][21][22][23] separation, 24 encapsulation, 25 forward osmosis, 26,27 CO 2 -switchable vesicles, [28][29][30][31] and CO 2 -switchable worm-like micelles. 4 Also, supercritical carbon dioxide (scCO 2 ), which is an environmentally friendly, non-flammable, and inexpensive solvent has found many new areas of interest in polymer synthesis due to the fact that as a polymerization medium it has negligible chain transfer and does not accumulate in the reaction.…”

Fabrication of amphiphilic fluorescent nanoparticles with an AIE feature via a one-pot clickable mercaptoacetic acid locking imine reaction: synthesis, self-assembly and bioimaging

“…73 For example, Yuan et al have demonstrated that particle size of amphiphilic copolymers could be well adjusted by CO 2 , which changes the hydrophilic/hydrophobic ratio of these copolymers. 73 Therefore, we could expect that the size and morphology may be also controlled by changing the proportion of Plys and AHAn. 1 H NMR spectroscopy is a powerful tool to prove that successful conjugation of hydrophilic Plys and hydrophobic AHAn.…”

When dual and multi-responsiveness meet molecular brushes

“…The ''smart'' materials have potential applications including catalysis, biosensors, controlled drug delivery, smart surfaces and tissue engineering. Nowadays, dual and multi-stimuli responsive polymers are of emerging interest [36][37][38][39][40][41][42][43][44][45][46]. The ''smarter'' polymers are sensitive to two or more stimuli and the versatility of these materials are greatly enhanced by the dual or multi-responsiveness.…”