Method for realizing one-pot synthesis of pH and temperature double-sensitive ionic micro hydrogel

Abstract

The invention relates to the field of environment-sensitive high polymer materials and aims to provide a method for realizing one-pot synthesis of pH and temperature double-sensitive ionic micro hydrogel. The method comprises the following steps: performing a free radical polymerization reaction on an N-alkyl acrylamide monomer, a double bond containing tertiary amine group, a polyhalogenated alkane compound and an initiator in an aqueous solution under oxygen-free conditions, dialyzing the obtained product for three days, performing ion exchange with organic cationic salt, and centrifuging to prepare the purified ionic micro hydrogel. The preparation method is simple and easily controllable, the obtained micro hydrogel has the pH and temperature double sensitivity, the excellent characteristics of the poly(ionic liquid) are introduced, and the micro hydrogel is high in purity, high in stability, high in swelling ratio and suitable for the fields of medicine controlled release and 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 and a preparation method thereof. Background technique

[0002] Microgel (microgel) is a kind of cross-linked polymer particles, which swells but does not dissolve in a good solvent, and has strong expansion-shrinkage. According to different solvents, polymer gels can be divided into hydrogels and organogels, among which the research on stimuli-responsive hydrogels has attracted people's attention. The external stimuli of environment-sensitive micro-hydrogels include temperature, pH value, solvent, salt concentration, light, sound field, electric field, pressure, etc. When subjected to these external stimuli, the micro-hydrogels will show corresponding responsiveness, reflecting An expansion or contraction change in volume. Utilizing this stimuli-responsive property, polymer gels can be used ...

Examples

Embodiment 1

[0036] 0.23g of temperature-sensitive monomer N-isopropylacrylamide (NIPAm), 0.028g of pH-sensitive monomer N-vinylimidazole (VIM), and 0.033g of dihaloalkane 1,4-dibromobutane were dissolved in desiccant In ionized water, stir under nitrogen atmosphere to make it fully dissolve, then add 0.025g initiator 2,2'-azobisisobutylamidine dihydrochloride, stir well, and carry out the following respectively under nitrogen atmosphere Subsequent processing:

[0037] (1) React at a constant temperature in an oil bath at 60°C for 6 hours. After dialysis and purification for 3 days, add 0.06g of organic cationic salt compound potassium fluoroborate for ion exchange reaction. The ion exchange reaction temperature is 25°C and the reaction time is 24 hours ; Then perform centrifugal washing to obtain pH and temperature dual sensitive ionic micro-hydrogel; or,

[0038] (2) React at a constant temperature in an oil bath at 70°C for 6 hours. After dialysis and purification for 3 days, add 0.06...

Embodiment 2

[0042] 0.23g temperature-sensitive monomer N-isopropylacrylamide (NIPAm), 0.028g pH-sensitive monomer N-vinylimidazole (VIM) and a certain amount of dihaloalkane 1,4-dibromobutane were dissolved in In deionized water, stir under nitrogen atmosphere to make it fully dissolved, then add 0.025g initiator 2,2'-azobisisobutylamidine dihydrochloride, stir well, under nitrogen atmosphere, at 70° Constant temperature reaction under C oil bath for 6 hours, after 3 days of dialysis and purification, add a certain amount of organic cationic salt compound to carry out ion exchange reaction, the ion exchange reaction temperature is 25 ℃, and the reaction time is 24 hours; Then carry out centrifugal washing, namely obtain An ionic microhydrogel with dual sensitivity to pH and temperature; the contents of 1,4-dibromobutane and organic cationic salts added are the following types, and the subsequent treatments are as follows:

[0043] or ,

[0044] or ,

[0045] (3) 0.033g of 1,4-dibromob...

Embodiment 3

[0048] 0.23g of temperature-sensitive monomer N-isopropylacrylamide (NIPAm), 0.028g of pH-sensitive monomer N-vinylimidazole (VIM) and 0.011g of dihaloalkane 1,4-dibromobutane were dissolved in desiccant In deionized water, stir under nitrogen atmosphere to make it fully dissolved, then add 0.025g initiator 2,2'-azobisisobutylamidine dihydrochloride, stir well, and place at 70°C under nitrogen atmosphere Reaction at constant temperature under the bath for 6 hours, after dialysis and purification for 3 days, add 0.023g lithium fluoroborate for ion exchange reaction, the ion exchange reaction temperature is 25°C, and the reaction time is 24 hours; then perform centrifugal washing to obtain pH and temperature double sensitive The ionic microhydrogel; the scanning electron micrograph of the pH and temperature dual-sensitive microhydrogel obtained by the copolymerization reaction is as follows Figure 4 As shown, the particle size is 50 nm.

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 and a preparation method thereof. Background technique

[0002] Microgel (microgel) is a kind of cross-linked polymer particles, which swells but does not dissolve in a good solvent, and has strong expansion-shrinkage. According to different solvents, polymer gels can be divided into hydrogels and organogels, among which the research on stimuli-responsive hydrogels has attracted people's attention. The external stimuli of environment-sensitive micro-hydrogels include temperature, pH value, solvent, salt concentration, light, sound field, electric field, pressure, etc. When subjected to these external stimuli, the micro-hydrogels will show corresponding responsiveness, reflecting An expansion or contraction change in volume. Utilizing this stimuli-responsive property, polymer gels can be used ...

Examples

Embodiment 1

[0036] 0.23g of temperature-sensitive monomer N-isopropylacrylamide (NIPAm), 0.028g of pH-sensitive monomer N-vinylimidazole (VIM), and 0.033g of dihaloalkane 1,4-dibromobutane were dissolved in desiccant In ionized water, stir under nitrogen atmosphere to make it fully dissolve, then add 0.025g initiator 2,2'-azobisisobutylamidine dihydrochloride, stir well, and carry out the following respectively under nitrogen atmosphere Subsequent processing:

[0037] (1) React at a constant temperature in an oil bath at 60°C for 6 hours. After dialysis and purification for 3 days, add 0.06g of organic cationic salt compound potassium fluoroborate for ion exchange reaction. The ion exchange reaction temperature is 25°C and the reaction time is 24 hours ; Then perform centrifugal washing to obtain pH and temperature dual sensitive ionic micro-hydrogel; or,

[0038] (2) React at a constant temperature in an oil bath at 70°C for 6 hours. After dialysis and purification for 3 days, add 0.06...

Embodiment 2

[0042] 0.23g temperature-sensitive monomer N-isopropylacrylamide (NIPAm), 0.028g pH-sensitive monomer N-vinylimidazole (VIM) and a certain amount of dihaloalkane 1,4-dibromobutane were dissolved in In deionized water, stir under nitrogen atmosphere to make it fully dissolved, then add 0.025g initiator 2,2'-azobisisobutylamidine dihydrochloride, stir well, under nitrogen atmosphere, at 70° Constant temperature reaction under C oil bath for 6 hours, after 3 days of dialysis and purification, add a certain amount of organic cationic salt compound to carry out ion exchange reaction, the ion exchange reaction temperature is 25 ℃, and the reaction time is 24 hours; Then carry out centrifugal washing, namely obtain An ionic microhydrogel with dual sensitivity to pH and temperature; the contents of 1,4-dibromobutane and organic cationic salts added are the following types, and the subsequent treatments are as follows:

[0043] or ,

[0044] or ,

[0045] (3) 0.033g of 1,4-dibromob...

Embodiment 3

[0048] 0.23g of temperature-sensitive monomer N-isopropylacrylamide (NIPAm), 0.028g of pH-sensitive monomer N-vinylimidazole (VIM) and 0.011g of dihaloalkane 1,4-dibromobutane were dissolved in desiccant In deionized water, stir under nitrogen atmosphere to make it fully dissolved, then add 0.025g initiator 2,2'-azobisisobutylamidine dihydrochloride, stir well, and place at 70°C under nitrogen atmosphere Reaction at constant temperature under the bath for 6 hours, after dialysis and purification for 3 days, add 0.023g lithium fluoroborate for ion exchange reaction, the ion exchange reaction temperature is 25°C, and the reaction time is 24 hours; then perform centrifugal washing to obtain pH and temperature double sensitive The ionic microhydrogel; the scanning electron micrograph of the pH and temperature dual-sensitive microhydrogel obtained by the copolymerization reaction is as follows Figure 4 As shown, the particle size is 50 nm.

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