Poly-N-vinylamides, complexation and conformational changes in aqueous solution

Poly(N‐vinylcaprolactam): A Thermoresponsive Macromolecule with Promising Future in Biomedical Field

“…Since PNVCL exhibits different solubility in different solvents, it is plausible that the addition of a co‐solvent into its aqueous solution should also affect its LCST . Taking alcohols as examples, most commonly used alcohols are good solvents for PNVCL; however, Ikeda and co‐workers reported that the addition of methanol gradually raised LCST up to ca.…”

“…Similar effect on LCST of polymer solutions upon the addition of methanol has been reported on PNIPAAm by Tirrell and co‐workers Furthermore, not only the fraction of co‐solvent could affect the LCST, but also the chemical nature of the solvent could also play an important role in the LCST. Taking alcohol as an example again, Kirsh et al reported that with the increase of alkyl chain length, addition of propanol or tert ‐butanol resulted in a decrease in LCST of PNVCL, unlike the effect of methanol and ethanol. The decrease in LCST was explained by the decreased acidity of OH groups due to the lower p K a for alcohols with longer alkyl chains.…”

“…The decrease in LCST was explained by the decreased acidity of OH groups due to the lower p K a for alcohols with longer alkyl chains. Moreover, the increase of the length of the alkyl chain of alcohol was also accompanied with an increase of the hydrophobic interaction between the hydrocarbon parts of alcohol and the partial dehydrated thermoresponsive polymer chain …”

Dynamic phase transition behavior and unusual hydration process in poly(ethylene oxide)-b-poly(N-vinylcaprolactam) aqueous solution

“…Besides specific cosolutes (like salts, surfactant, and ionic liquids) and cosolvents which had been applied to manipulate phase transition behavior of PVCL‐based systems, copolymerization had also been utilized to regulate phase transition behavior and morphology of thermoresponsive polymers by shifting the hydrophilic/hydrophobic balance. In general, the introduction of hydrophilic comonomers increases the LCSTs whereas hydrophobic comonomers induce an opposite effect .…”

Heterogeneous Morphology of Random Copolymer Microgels as Reflected in Temperature‐Induced Volume Transition and1H High‐Resolution Transverse Relaxation NMR

“…This polymer is soluble in water in temperature range between 0 and 30 ° C. The heating of the aqueous PVCL solution above LCST around 32 ° C leads to the phase separation and precipitation of the polymer. [4][5][6] PVCL is not only water soluble and thermally sensitive, but also biocompatible polymer. It contains hydrophilic amide group that is directly connected to the hydrophobic carboncarbon backbone chain so that its hydrolysis will not produce small amide compounds that are often bad for biomedical applications.…”