Molecular blotting polymer microsphere of surface hydrophilicity and preparation method thereof
Affiliated technical field
The present invention relates to a kind of preparation method in pure water solution system with the molecular blotting polymer microsphere of excellent molecular recognition function, specifically just relate to a kind of surface and have the preparation method of the molecular blotting polymer microsphere of hydrophilic macromolecule brush.
Background technology
Molecular imprinting is the emerging cross discipline growing up on the subject bases such as polymer chemistry, biochemistry, materials chemistry and bionics techniques in recent years.Molecularly imprinted polymer therefrom (Molecularly Imprinted Polymers, be called for short MIPs) there is compatibility and single-minded selective, the good stability to guest molecule excellence and prepare the advantages such as easy, thereby become the focus of molecular recognition area research in the world.At present, molecularly imprinted polymer is mainly prepared by traditional free radical polymerisation process, and specific implementation method comprises mass polymerization, suspension polymerization, emulsion polymerization, two step swelling method and precipitation polymerization methods.The molecularly imprinted polymer that wherein mass polymerization obtains need to grind, and wastes time and energy; Suspension polymerisation and emulsion polymerisation need special dispersant; Two step swelling method complex operations; And precipitation polymerization method is without special dispersing agent, can a step prepare monodispersed polymer microballoon, product does not need to grind, simple to operate, and purposes is very extensive.Up to now, people have synthesized the MIPs of numerous template molecules, its application study has also expanded to numerous aspects such as chromatographic stationary phases, solid phase extractions, biosimulation detection and sensor, artificial enzyme, organic synthesis and drug delivery, and demonstrates huge application prospect in fields such as food and Environmental security detections.
Although molecular engram research has obtained huge progress, in some application, even entered the commercialization stage, but in this research field, still there are some critical puzzle and challenges, greatly limited molecularly imprinted polymer material and applied widely.One of them be how to prepare the MIPs in the aqueous solution with excellent molecular recognition performance.The molecularly imprinted polymer growing up so far only just can demonstrate excellent molecular recognition performance conventionally in organic solution system, and the molecularly imprinted polymer that really can be applicable to water solution system is very limited.But from economically, ecology and the each side such as environmental protection consider, with water, replace organic solvent to be all very important; From its potential application biological technical field, considering, is necessary take water as solvent; And practical application in the fields such as environment and food safety detection with regard to it is used the molecularly imprinted polymer in the aqueous solution with excellent molecular recognition performance can reach the object of direct fast detecting.The molecularly imprinted polymer that visible exploitation is suitable for water solution system has extremely important theory significance and practical value.
Recently, the people such as B.Sellergren have reported by introduce hydrophilic monomer 2-hydroxyethyl methacrylate in molecular engram system, improve the surface hydrophilicity of molecularly imprinted polymer, finally obtained being suitable for the molecularly imprinted polymer (J.Am.Chem.Soc.2003,125:15101-15109) of water solution system.But the method need to, through a large amount of high flux condition optimizing experiments, greatly limit it and apply widely.The people such as J.Haginaka carry out surface hydrophilic modification (Anal.Chem.2000 by the free yl graft polymerization method of monomethyl acrylic acid glyceride and dimethyl allene acid glyceride to molecular engram microsphere, 72:5206-5210), result show the molecule distinguishability of this type of molecularly imprinted polymer in pure water solution system not be improved significantly.There is the problems such as the inhomogeneous and polymerization process of surface coverage is uncontrollable to the surface hydrophilic modification of molecular blotting polymer microsphere in above-mentioned common free radical surface aggregate method, to such an extent as to can affect the molecule distinguishability of product.Therefore develop and a kind ofly obtain easily that to be suitable for the new method of molecularly imprinted polymer of water solution system significant.
This work organically combines controllable free-radical polymerisation technology and molecular engram research, by reversible addition-cracking chain is shifted to (RAFT) mechanism of polymerization, introduce precipitation polymerization process, having realized one-step method preparation table mask has living chain to shift the molecular blotting polymer microsphere of group.Then take it as immobilized chain-transferring agent, cause the controllable polymerization of hydrophilic monomer, obtain surface and there is the molecular blotting polymer microsphere that hydrophilic macromolecule is brushed.Because RAFT polymerization has reaction condition gentleness, the advantages such as the wide and polymerization process height of suitable monomers scope is controlled, therefore adopt method that RAFT precipitation polymerization combines with RAFT surface aggregate can control easily the various parameters of gained molecular blotting polymer microsphere and surface hydrophilicity polymer brush thereof, the final surface that obtains has suitable hydrophilic molecular blotting polymer microsphere, thereby realizes the object of preparing the molecular blotting polymer microsphere that is suitable for water solution system.
Summary of the invention
The present invention aim to provide a kind of simple and easy to do preparation be suitable for water-soluble system molecular blotting polymer microsphere new method, to make up the deficiencies in the prior art, for improving the molecule distinguishability of molecularly imprinted polymer in water solution system, provide theory and experimental basis.
Technical conceive of the present invention is by molecular imprinting, precipitation polymerization process and RAFT controllable free radical polymerization process are combined, first prepare narrow diameter distribution, template molecule is had to single-minded recognition capability and the surperficial molecular blotting polymer microsphere with living chain transfer group, the RAFT of the hydrophilic monomer then causing by surface is aggregated in molecular blotting polymer microsphere surface grafting hydrophilic macromolecule brush, obtains being suitable for the molecular blotting polymer microsphere of the aqueous solution.
Concrete grammar of the present invention is as follows:
(1) by template molecule, function monomer, crosslinking agent in molar ratio: 1~2: 4~10: 16~60 feed intake, function monomer and the crosslinking agent volume fraction in system is 0.5~5%.
(2) add the initator of function monomer and the about 1-4% of crosslinking agent total amount, and initator and chain-transferring agent mol ratio are 1: 2~5.
(3), after said mixture is dissolved completely, logical argon gas or nitrogen 5~60min, remove oxygen.Reactor sealing is placed in 50~100 ℃ of oil baths and reacts 6~48h, ultrasonic dispersion 5~30min, filtration obtains the molecular blotting polymer microsphere that contains template molecule.
(4) the mixed liquor Soxhlet extracting that is 10/1~10/10 by methyl alcohol/acetic acid volume ratio for the molecular blotting polymer microsphere that contains template molecule 12~72 hours, then with methyl alcohol or the extracting of acetonitrile Soxhlet 12~48 hours, until do not have template molecule to wash out.Then in 20~60 ℃ of vacuum drying to constant weight, obtain narrow diameter distribution, single dispersion and the surperficial molecular blotting polymer microsphere with RAFT chain transfer group.
(5) by hydrophilic monomer, initator and free chain-transferring agent in molar ratio 100~5000: 1~10: 2~40 feed intake, the volume fraction > 60% of solvent in reaction system, and the surface that adds certain mass has the molecular blotting polymer microsphere of RAFT chain transfer group in reaction bulb, after degassed deoxygenation, reaction bulb is placed in to the oil bath of 50~90 ℃, after reaction 6~48h.By product centrifuge washing, 40 ℃ of vacuum drying 48h, obtain the molecular blotting polymer microsphere that surface grafting hydrophilic polymer molecules is brushed.
Function monomer used is: 4-vinylpyridine, 2-vinylpyridine, 2-hydroxyethyl methacrylate, acrylamide or NVP.
Crosslinking agent used is: GDMA (EDMA), trimethyl acrylic acid trihydroxy methyl propyl ester (TRIM), divinylbenzene (DVB) or N, N '-methylene-bisacrylamide.
Initator used is: azo or peroxide radical initiator.
Chain-transferring agent used is: two thioesters or three thioesters.
Solvent used is: acetonitrile, methyl alcohol, toluene, DMF (DMF), chloroform or methanol/water (4/1).
The template molecule adopting is: theophylline, caffeine, bisphenol-A, orfloxacin, estradiol, 2,4-dichlorphenoxyacetic acid (2,4-D) or inderal.
Hydrophilic monomer used is: 2-hydroxyethyl methacrylate, NIPA, acrylamide, N, N '-DMAA or Dimethylaminoethyl Methacrylate.
Accompanying drawing explanation:
Fig. 1. surface has the preparation process schematic diagram of the molecular blotting polymer microsphere of hydrophilic macromolecule brush.
Fig. 2. the surface that utilizes RAFT precipitation polymerization to prepare has living chain shifts the electron scanning micrograph of the molecular blotting polymer microsphere (with 2,4-D for template molecule) of group.
Fig. 3. the surface that utilizes RAFT precipitation polymerization to prepare has the electron scanning micrograph of the non-imprinted polymer microballoon (corresponding to the MIP in Fig. 2) of living chain transfer group.
Fig. 4. the surface that utilizes RAFT polymerization reaction on the solid surface to prepare has the electron scanning micrograph of the molecular blotting polymer microsphere (with 2,4-D for template molecule) of hydrophilic macromolecule brush.
Fig. 5. the surface that utilizes RAFT polymerization reaction on the solid surface to prepare has the electron scanning micrograph of the non-imprinted polymer microballoon (corresponding to the MIP in Fig. 4) of hydrophilic macromolecule brush.
Fig. 6. surface has chain shifts molecular blotting polymer microsphere (with 2,4-D for template molecule, filled symbols) and non-imprinted polymer microballoon (open symbols) absorption property to 2,4-D in pure water solution thereof of group.
Fig. 7. surface has molecular blotting polymer microsphere (with 2,4-D for template molecule, filled symbols) and non-imprinted polymer microballoon (open symbols) absorption property to 2,4-D in pure water solution thereof of hydrophilic macromolecule brush.
The specific embodiment
Example 1
By 0.25mmol 2,4-D adds in the 250mL round-bottomed flask that 60mL methanol/water (4: 1, v/v) are housed, and magneton stirs it is dissolved completely, then adds the 4-vinylpridine of 1mmol.Fully contact after half an hour, add respectively again the methanol/water (4: 1, v/v) of 5mmolEDMA, 0.44mmol chain-transferring agent dithiobenzoic acid isopropyl phenyl ester (CDB), 0.22mmol azodiisobutyronitrile (AIBN) and 20mL.Stir after half an hour, after logical argon gas deoxygenation 30min, by reaction system sealing, be placed in 60 ℃ of constant temperature oil baths, reaction 24h, suction filtration obtains product.
Product is carried out to 48h Soxhelt extracting with methyl alcohol/acetic acid (9: 1, v/v), then use methyl alcohol Soxhelt extracting 12h.Dry rear 40 ℃ of vacuum drying 48h, obtain narrow diameter distribution and the surperficial molecular blotting polymer microsphere with RAFT chain transfer group.
In the preparation of non-imprinted polymer microballoon, except not adding template molecule, other processes are the same.
By the CDB of the AIBN of 1mg, 5mg, 2.04g N, N '-DMAA, is dissolved in 5mL DMF, then adds 100mg surface to have chain and shifts the molecular blotting polymer microsphere of group in reaction bulb, after degassed deoxygenation, 24h is reacted in the oil bath that system is placed in to 70 ℃.Then by product centrifuge washing, 40 ℃ of vacuum drying 48h, obtain the molecular blotting polymer microsphere that surface grafting hydrophilic polymer molecules is brushed.
The non-imprinted polymer method for preparing microsphere of surface grafting hydrophilic polymer molecules brush is the same.
Example 2
By 2 of 0.25mmol, 4-D adds in the 250ml round-bottomed flask that 60ml methanol/water (4: 1, v/v) are housed, and magneton stirs it is dissolved completely, then adds the 4-vinylpridine of 1mmol.Fully contact after half an hour, then add respectively the methanol/water (4: 1, v/v) of 5mmolEDMA, 0.44mmol chain-transferring agent CDB, 0.22mmol AIBN and 20ml.Stir after half an hour, after logical argon gas deoxygenation 30min, by reaction system sealing, be placed in 60 ℃ of constant temperature oil baths, reaction 24h, suction filtration obtains product.
Product is carried out to 48h Soxhelt extracting with methyl alcohol/acetic acid (9: 1, v/v), then use methyl alcohol Soxhelt extracting 12h.Dry rear 40 ℃ of vacuum drying 48h, obtain narrow diameter distribution and the surperficial molecular blotting polymer microsphere with RAFT chain transfer group.
In the preparation of non-imprinted polymer microballoon, except not adding template molecule, other processes are the same.
By 1mg AIBN, 5mg CDB, 2.6g hydroxyethyl methacrylate, be dissolved in 5mL DMF, then add 100mg surface to there is the molecular blotting polymer microsphere of chain transfer group, reaction system is after degassed deoxygenation, and 24h is reacted in the oil bath that is placed in 70 ℃.By product centrifuge washing, 40 ℃ of vacuum drying 48h, obtain the molecular blotting polymer microsphere that surface grafting hydrophilic polymer molecules is brushed.
The preparation method of the non-imprinted polymer microballoon of surface grafting poly hydroxy ethyl acrylate polymer brush is the same.
Example 3
0.25mmol theophylline and 30mL acetonitrile are added in the round-bottomed flask of 100mL, stirring is dissolved it completely, then add 1mmol methacrylic acid, fully mix after half an hour, more successively add 4mmol EDMA, 0.09mmol chain-transferring agent CDB, 0.045mmol AIBN and 10mL acetonitrile.Stir after half an hour, logical argon gas deoxygenation 30min, by reaction system sealing, is placed in 60 ℃ of constant temperature oil baths, reaction 24h, and suction filtration obtains product.
Resulting polymers microballoon is carried out to 48h Soxhelt extracting with methyl alcohol/acetic acid (9: 1, v/v), then use acetonitrile Soxhelt extracting 24h.Then in 40 ℃ of vacuum drying 48h, obtain narrow diameter distribution and the surperficial molecular blotting polymer microsphere with chain transfer group.
The preparation process of non-imprinted polymer microballoon is not except adding template, and other are the same.
By the CDB of the AIBN of 1mg, 5mg, 2.6g hydroxyethyl methacrylate, be dissolved in 5mL DMF, then add 100mg surface to have the molecular blotting polymer microsphere of chain transfer group, after degassed deoxygenation, 24h is reacted in the oil bath that system sealing is placed in to 70 ℃.By product centrifuge washing, 40 ℃ of vacuum drying 48h, obtain the molecular blotting polymer microsphere of surface grafting hydrophily poly hydroxy ethyl acrylate molecular brush.
The preparation method of the non-imprinted polymer microballoon of surface grafting hydrophily poly hydroxy ethyl acrylate polymer molecule brush is the same.
Example 4
0.25mmol theophylline and 30mL acetonitrile are added in the round-bottomed flask of 100mL, stirring is dissolved it completely, then add 1mmol methacrylic acid, fully mix after half an hour, more successively add 4mmol EDMA, 0.09mmol chain-transferring agent CDB, 0.045mmol AIBN and 10mL acetonitrile.Stir after half an hour, logical argon gas deoxygenation 30min, by reaction system sealing, is placed in 60 ℃ of constant temperature oil baths, reaction 24h, and suction filtration obtains product.
Resulting polymers microballoon is carried out to 48h Soxhelt extracting with methyl alcohol/acetic acid (9: 1, v/v), then use acetonitrile Soxhelt extracting 24h.Then in 40 ℃ of vacuum drying 48h, obtain narrow diameter distribution and the surperficial molecular blotting polymer microsphere with chain transfer group.
The preparation process of non-imprinted polymer microballoon is not except adding template, and other are the same.
By the CDB of the AIBN of 1mg, 5mg, 2.04g Dimethylaminoethyl Methacrylate, be dissolved in 5mL DMF, then add 100mg surface to have the molecular blotting polymer microsphere of chain transfer group, after degassed deoxygenation, 24h is reacted in the oil bath that system sealing is placed in to 70 ℃.By product centrifuge washing, 40 ℃ of vacuum drying 48h, obtain the poly-N of surface grafting hydrophily, the mark polymer microballoon of NIPA molecular brush.
The preparation method of the non-imprinted polymer microballoon of surface grafting hydrophily polymethylacrylic acid dimethylamino polymerizable methacrylate thing molecular brush is the same.