Preparation method for pH and temperature dual-sensitive ion micro-hydrogel

Abstract

The invention relates to the field of environment-sensitive type high polymer materials and aims at providing a preparation method for a pH and temperature dual-sensitive ion micro-hydrogel. The preparation method comprises the following steps of: carrying out free-radical copolymerization to N-alkyl acrylamide monomer, a double-bond compounding containing a tertiary amine radical and initiator in anhydrous solvent 1,4-dioxane or tetrahydrofuran under the oxygen-free condition; extracting binary copolymer by adopting diethyl ether or petroleum ether as a precipitant, and vacuum-drying the binary copolymer until the weight is constant after the centrifugal separating; preparing the obtained binary copolymer into aqueous solution; adding polyhalogenated alkane compound to the aqueous solution, and stirring the solution at the constant temperature of 40 DEG C to 70 DEG C; and adding an organic cation salt compound after the mixture is purified, and stirring the mixture under the room temperature to obtain the pH and temperature dual-sensitive ion micro-hydrogel. The preparation method provided by the invention is simple and easy to control, and the obtained micro-hydrogel has dual sensitivities of pH and temperature; and moreover, excellent characteristics of the polyion liquid are introduced, the purity is high, the stability is good and the swelling rate is high, so that the preparation method is suitable for the fields such as controlled slow release of the medicines, the sensors and the like.

Description

technical field [0001] The invention relates to the field of environment-sensitive polymer materials, in particular to an ion microhydrogel with dual sensitivity to pH and temperature, a preparation method and application thereof. Background technique [0002] Hydrogel is cross-linked to form a hydrophilic polymer network because of the physical or chemical bonds inside it. Water can only penetrate into the chains of the polymer network and form a gel through swelling, which can only swell but not dissolve in water. Due to the high water content and biocompatibility, hydrogels have very good application prospects in biomedicine, and have received extensive attention from scientific researchers. Microgel (microgel) is a cross-linked latex particle with colloidal size (1nm~10μm) swollen in a good solvent, and its molecular structure is between the branched macromolecule and the polymer macroscopic network structure. According to whether there are responsive groups in the mole...

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Problems solved by technology

The particle hydrodynamic diameter at the isoelectric point of the ampholyte microgel is 105.7nm, but the particle size distribution is wide, and the preparation method is cumbersome and the purification process is complicated

[0007] Chinese patent CN101037494A discloses a kind of main monomers such as N-isopropylacrylamide and acrylic acid, in the presence of chemical cross-linking agent, adopts specific dropping technology and soap-free emulsion polymerization method to prepare pH and temperature dual sensitivity Micro-hydrogel, the particle size of the micro-hydrogel is 40-400nm, but the monomer and the chemical cross-linking agent react at the same time during the preparation process, because the reaction consumption rate of the chemical cross-linking agent is much faster than the reaction speed of the monomer, The cross-linking degree inside the micro-hydrogel is uneven, which affects the microstructure and physical properties of the micro-hydrogel; at the same time, the purification process is long, requiring 1-3 weeks of dialysis or repeated 3-6 times of high-speed centrifugation and ultrasound redistribute

[0008] The preparation method of the hydrogel involved in the above patents is cumbersome, the purification process is complicated, or the size of the obtained product is too large or the size distribution is wide, which is not conducive to industrial production and further scientific research

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