Thermosensitive properties of semi-IPN gel composed of amphiphilic gel and zwitterionic thermosensitive polymer in buffer solutions containing high concentration salt

Abstract

In this study, a semi-interpenetrating polymer network (semi-IPN) gel, which consists of an amphiphilic N,N-dimethylacrylamide-coN -isopropylacrylamide (DMAA-co-NIPAM) gel and an interpenetrating zwitterionic thermosensitive poly(N-isopropylacrylamide-coN ,N-dimethyl(acrylamidopropyl)ammonium propane sulfonate) (poly(NIPAM-co-DMAAPS)) was prepared. The thermosensitive behavior of the semi-IPN gel was investigated in a buffer solution composed of a relatively high concentration of sodium chloride and sodium citrate as salts, and sodium dodecyl sulfate as a surfactant, which are generally used as a buffer solution in biochips. At low temperatures, the semi-IPN gel in the buffer solution was absolutely transparent; however, when the gel was heated, the gel became milky white or opaque without a large change in the gel size. The network of the transparent gel is homogeneous, whereas that of the opaque gel consists of coarse and dense parts. Such a structural change in the gel network was confirmed by the temperature dependence of the permeability of the buffer solution through the semi-IPN gel membrane. The permeability increased drastically when the gel became opaque because of heating.

One-pot synthesis of responsive sulfobetaine nanoparticles by RAFT polymerisation: the effect of branching on the UCST cloud point

“…9 Polysulfobetaines are interesting for various reasons, including 50 their antipolyelectrolyte behaviour in aqueous salt solution and bio-and haemo-compatible properties, 10, 11 making them suitable for many applications including dispersing agents, pharmaceutics and viscosifying fluids. Several polysulfobetaines exhibit UCST behaviour in water including the methacrylate shown in Figure 1, 55 the acrylamide 12 and the methacrylamide. 13 The methacrylate polymers were first synthesised directly by free radical polymerisation and their cloud point behaviour was studied.…”

The Properties of Thermosensitive Zwitterionic Sulfobetaine NIPAM-<i>co</i>-DMAAPS Polymer and the Hydrogels: The Effects of Monomer Concentration on the Transition Temperature and Its Correlation with the Adsorption Behavior

“…Poly(N-isopropylacrylamide) [poly(NIPAM] is a thermosensitive polymer with Low Critical Solution Temperature (LCST) which is around 32 °C. NIPAM swells at low temperature and shrinks at high temperature because of its transition from hydrophilic to hydrophobic and has neutral charge [14]. N,N'-dimethyl (acrylamidopropyl)ammonium propane sulfonate (DMAAPS) is zwitterionic sulfobetaine polymer.…”

“…That polymer completely dissolves in NaCl solution at room temperature as same as in water at a temperature above the UCST [15]. Takahashi [14] has studied the thermosensitive polymer property of NIPAM-co-DMAAPS in a salt solution. The LCST of poly(NIPAM-co-DMAAPS) increases along with the increase of DMAAPS concentration and decreases along with the increase of the salt solution concentration.…”

Effects of specific anions on the relationship between the ion-adsorption properties of sulfobetaine gel and its swelling behavior

“…Various zwitterionic betaine gels, such as phosphobetaine [1e3], sulfobetaine [4e6], carboxybetaine [7,8], semiinterpenetrating network (IPN) gel composed of amphiphilic gel and zwitterionic betaine polymers [9,10], and chemicalephysical cross-linked double network (DN) gel, which was obtained by introducing ductile physical networks into the network of chemically cross-linked polysulfobetaine gels [11], have shown excellent chemical stability [12], good biocompatibility [13], ultralow fouling [14,15], and excellent mechanical properties [14,16]. Studies on the properties of polymers or gels based on betaine have received significant attention in the scientific community.…”

“…It also offers potential improvement of the ion selectivity toward adsorption because the cations and anions in the solution can bond via both the negative and positive charges located in the same repeating unit [17e19]. Betaine polymers are generally thermosensitive in aqueous solutions [9,16,20]. The transition temperature, which is also referred to as the upper critical solution temperature (UCST), of sulfobetaine polymers varies over a wide range by altering the surrounding conditions and polymer characteristics, such as length of the alkylene spacer groups [16,20].…”