Thermosensitive properties of semi‐IPN gel composed of amphiphilic gel and thermosensitive polymer in buffer solution

Abstract

In this study, a semi-interpenetrating polymer network (semi-IPN) gel comprising a crosslinked amphiphilic N,N-dimethylacrylamide-co-N-isopropylacrylamide gel and interpenetrating thermosensitive poly(Nisopropylacrylamide) (poly(NIPAM)) was prepared. Their thermosensitive behaviors in a buffer solution comprising sodium chloride, sodium citrate, and sodium dodecyl sulfate, which are generally used in biochips, were investigated. At low temperatures, the gel in the buffer solution was absolutely transparent. However, when the gel was heated, it became milky white or opaque without changes in the gel size. It is well known that the network or crosslink distribution of the transparent gel is homogeneous macroscopically, whereas that of the opaque gel is inhomogeneous; in other words, the network of the opaque gel consists of coarse and dense parts. The structural changes in the gel network were confirmed by the temperature dependence of the permeability of the buffer solution through the semi-IPN gel membrane. The permeability increased stepwise when the gel became opaque due to heating. The structural changes in the semi-IPN gel network depended on the compositions of the buffer solution and gel, i.e., the copolymerization ratio of NIPAM in the gel and the content of the poly(NIPAM) molecules in the gel. These results suggest that the thermosensitive behaviors of the semi-IPN gel strongly depend on the interactions between the copolymerized NIPAM in the gel network and the poly(NIPAM) molecules.

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

“…In order to alleviate this problem, we proposed a semi-interpenetrating polymer network (semi-IPN) gel, which consists of an amphiphilic gel and an interpenetrating thermosensitive polymer [6]. Thermosensitive polymers are soluble in water below their lower critical solution temperature (LCST) and gel is transparent; however, they are insoluble in water above the LCST.…”

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.…”

Controlled release of bovine serum albumin from stimuli‐sensitive silk sericin based interpenetrating polymer network hydrogels

“…IPN hydrogels, especially hybrids of synthetic and natural polymers, with altered morphologies, perform better with a synergistic combination of homopolymer properties. In recent years, there has been a great deal of research interest in the development of stimulus‐sensitive IPN hydrogels . These hydrogels can respond to external stimuli and simultaneously exhibit some abrupt changes in the physical or chemical nature of the hydrogel network.…”