Crosstalk between responsivities to various stimuli in multiresponsive polymers: change in polymer chain and external environment polarity as the key factor

Interplay of Composition, pH, and Temperature on the Conformation of Multi-stimulus-responsive Copolymer Brushes: Comparison of Experiment and Theory

“…Stimulus-responsive macromolecules are ubiquitous in nature and are of particular interest for industrial and biomedical applications. , A push toward synthetic polymers with properties that can be modified by the application of two or more stimuli has occurred in recent years because of their increased versatility and usage, particularly for medical applications such as cancer treatment. − Polymers of this nature are particularly attractive for biomedical applications where a variety of responses is advantageous as they are able to mimic multi-stimulus-responsive proteins and other biochemical molecules. ,,,− Grafting these polymers from a surface in a brush regime allows for the manufacture of responsive coatings with controllable interfacial properties. , …”

“…In fact, through the combination of different monomers in different ratios and architectures, a wide variety of responsive copolymers with unique behaviors and properties can be synthesized. The reader is directed to a number of recent reviews covering the cornucopia of multi-stimulus-responsive copolymers including brushes. − A number of examples of multi-stimulus-responsive polymers are exemplified below to give direct context to the work presented here. The reader is further directed to a number of relevant multi-stimulus-responsive copolymer examples which are not discussed for brevity. − …”

Cyclic Water Storage Behavior of Doubly Thermoresponsive Poly(sulfobetaine)-Based Diblock Copolymer Thin Films

“…An elegant way to induce the absorption and release of small molecules is the use of stimuli-responsive materials, which react strongly to external stimuli such as temperature, relative humidity (RH), illumination, and salt concentration. − Hence, parameters that are easy to control, for example, temperature or RH, can be used to change the mechanical properties and the dimensions of a thin film from responsive polymers. Representatives of the class of thermoresponsive polymers are poly­(sulfobetaine)­s (PSBs), which in aqueous solution, show a miscibility gap below their upper critical solution temperature (UCST). − This is highly unusual as UCST-like behavior is rather observed for polymers in organic solvents but not in aqueous solvents. , Other zwitterionic polymers, such as poly­(phosphatidylcholine)­s and poly­(carboxybetaine)­s, are generally not thermoresponsive in aqueous solution. − In addition to their special solution behavior, their high biocompatibility qualifies PSBs as antifouling coatings and for biomedical applications. ,− In contrast, nonionic thermoresponsive polymers, such as poly­( N -isopropylacrylamide) and poly­( N -isopropylmethacrylamide) (PNIPMAM), usually show a miscibility gap above their lower critical solution temperature (LCST), which is the result of changes in hydrophilicity and the number of hydrogen bonds between water molecules and the polymer chains. − …”

Temperature Behavior of Aqueous Solutions of Poly(2-Oxazoline) Homopolymer and Block Copolymers Investigated by NMR Spectroscopy and Dynamic Light Scattering

“…The polymers that can change their properties upon external stimuli, such as changes in temperature, pH, ionic strength, magnetic field, and light irradiation, as well as by applying ultrasound or enzyme, reactive oxygen species (ROS), or glucose addition, are called “smart” or stimuli-responsive polymers [ 1 , 2 , 3 , 4 , 5 , 6 ]. Over the past decades, they have become one of the most intensively studied class of materials because of their potential biomedical applications (i.e., drug/gene/DNA delivery, biosensors, bio-imaging agents) or tissue engineering applications [ 1 , 7 , 8 , 9 , 10 , 11 , 12 ].…”