Hydration Changes during Thermosensitive Association of a Block Copolymer Consisting of LCST and UCST Blocks

Abstract

Summary: Thermosensitive association of a diblock copolymer consisting of poly(3‐dimethyl(methacryloyloxyethyl) ammonium propane sulfonate) (PdMMAEAPS), as an upper critical solution temperature (UCST) block, and poly(N,N‐diethylacrylamide) (PdEA), as a lower critical solution temperature (LCST) block, has been investigated by using IR spectroscopy. The ν(CO) and ν(SO) bands of the PdMMAEAPS block and the amide I band of PdEA block critically changed at the UCST and LCST, respectively, indicating that the segmental interaction of each block is altered at each transition.The double temperature responsiveness of a UCST block and LCST block containing diblock copolymer. Micelles form at temperatures both below the UCST and above the LCST of the blocks.magnified imageThe double temperature responsiveness of a UCST block and LCST block containing diblock copolymer. Micelles form at temperatures both below the UCST and above the LCST of the blocks.

Structures and Synthesis of Zwitterionic Polymers

“…Furthermore, the combination of hydrophilicity and tolerance to high ionic strength makes polyzwitterions attractive candidates for hydrogels or viscosity modifiers in aqueous media under extreme conditions, such as oil field applications. Interestingly, many polyzwitterions show an upper critical solution temperature (UCST) in aqueous media [19,[42][43][44][45][46][47][48]. This has been exploited in recent years for designing stimuli-responsive polymer systems [49][50][51] from polyzwitterions, being reversibly sensitive to changes in temperature, ionic strength, specific ion pairing, and chemical reactions, or, more rarely, to changes in pH (see Section 4.2).…”

“…RDRP techniques offer direct access to polymers bearing zwitterionic groups with previously unthinkable features, such as predefined molar masses and narrow molar mass distributions [163,[182][183][184][185][186][187][188][189] as well as well-defined functional end groups [61,166,182,[190][191][192][193][194][195][196][197][198][199][200][201][202][203][204][205][206][207][208]. Moreover, complex architectures, such as block copolymers [14,[46][47][48]166,167,169,173,187,, graft copolymers [164,213,237,[241][242][243][244]…”

“…Polyzwitterions in aqueous solution, for instance, are known to show frequently a thermal coil-collapse transition of the upper critical solution (UCST) type. Characteristically, the UCST-transition can be modulated by adding specific salts [19,[42][43][44][45][46][47][48]. As these are physico-chemical effects, they are outside the scope of this review.…”

Switchable Materials Containing Polyzwitterion Moieties

“…Maeda et al [92] prepared a double-responsive diblock copolymer consisting of poly (38) as a USCT block and poly(N,N-diethylacrylamide) as an LCST block. By using FTIR and DSC techniques, the mechanism of micelles formation below USCT and above LCST based on selective hydration of the blocks at different temperatures was explained.…”

Tissue engineering scaffold electrospun from poly(ε- caprolactone)-b-poly(sulfobetaine methacrylate) block copolymers with improved hydrophilicity and good cytocompatibility

“…Liu et al reported the preparation of thermosensitive PCL-PEG copolymer hydrogel, and investigated their physical-chemical properties and drug delivery behavior [16]. To the best of our knowledge, very few papers reported on copolymers composed of hydrophobic PCL and hydrophilic PSBMA segments [17][18][19].…”