CN104877116B - The preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL - Google Patents

Abstract

The present invention relates to the preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL.The technical scheme is that with Nano-meter SiO_2₂Microballoon (SNP) is hard template, anchors azo-initiator ACPA at silicon ball surface, obtains SNP ACPA；With SNP ACPA as initiator, mercaptoethanol is chain-transferring agent, causes the polymerization of N caprolactam, obtains SNP g PNVCL OH；With ε caprolactone as monomer, SNP g PNVCL OH is initiator, and stannous octoate is catalyst, and BCY is crosslinking agent, obtains SNP g PNVCL b cPCL；By SNP g PNVCL b cPCL hf etching, at low temperatures, pulverize with cell disruptor, obtain target product.Instant invention overcomes the many harsh conditions preparing flexible polymer Janus nanometer sheet, obtain a kind of method with universality.

Description

The preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL

Technical field

The invention belongs to the field of chemical synthesis, more particularly to the system of a kind of flexible polymer Janus nanometer sheet PNVCL/cPCL Preparation Method.

Background technology

Janus originates from the two-sided god that ancient Roman is mythical, legend he have two contrary faces, one side to hope to the past, one side is hoped To future.De Gennes describes, with Janus mono-word, the different chemical character that particle surface has simultaneously in 1991 first.Janus Particle is the most special a kind of particle, and two parts of this particle have different structures or chemical composition, the most inorganic With organic, nonmetal with metal, nonpolar with polarity, anion with cation, neutral with electrically charged, hydrophobic and hydrophilic Deng.The shape of Janus particle is also diversified, such as half strawberry shape particle, acorn shape particle, snowman particle etc..

On the basis of Janus particle, people begin to focus on Janus flaky material.This is because spheric granules itself has ball Property symmetry, and anisotropic Janus flaky material has more abundant phase behavior, for Janus sheet, not only chemical group One-tenth is non-centrosymmetrical, and its pattern is also non-centrosymmetrical.Compared with the inorganic Janus nanometer sheet of rigidity, flexible polymer Thing Janus nanometer sheet has more abundant Assembling Behavior, has more preferable toughness, and is easier to make for functionalization.Existing The method preparing Janus flaky material is complicated, and condition is harsh, does not has universality.

Poly-N-vinylcaprolactam (PNVCL) is a kind of good temperature sensitive polymer, has nontoxicity, biology The advantages such as compatibility is good, have broad application prospects at biomedical sector.

Polycaprolactone (PCL) has good degradability and biocompatibility, and the end product of degraded is CO₂And H₂O, It is harmless to human non-toxic, so PCL is widely used at pharmaceutical carrier and organ engineering field.

Summary of the invention

The invention aims to overcome the many harsh conditions preparing flexible polymer Janus nanometer sheet, thus obtain one The method with universality.

To achieve these goals, the technical solution used in the present invention is: flexible polymer Janus nanometer sheet PNVCL/cPCL Preparation method, comprise the steps:

1) with Nano-meter SiO_2₂Microballoon (SNP) is hard template, anchors azo-initiator 4 at silicon ball surface, double (the 4-cyanogen of 4'-azo Base valeric acid) (ACPA), obtain intermediate 1 (SNP-ACPA)；

2) with intermediate 1 (SNP-ACPA) as initiator, mercaptoethanol is chain-transferring agent, causes N-caprolactam (NVCL) polymerization, obtains intermediate 2, i.e. obtains the Nano-meter SiO_2 of terminal hydroxy group PNVCL grafting₂Microballoon (SNP-g- PNVCL-OH)；

3) with 6-caprolactone as monomer, intermediate 2 (SNP-g-PNVCL-OH) is initiator, and stannous octoate is catalyst, Bis (ε-caprolactone-4-yl) (BCY) is crosslinking agent, obtains intermediate 3, i.e. obtains the polymer overmold of outer layer crosslinking Nano silica microsphere (SNP-g-PNVCL-b-cPCL)；

4) by intermediate 3 (SNP-g-PNVCL-b-cPCL), with hf etching, at 0-5 DEG C, carry out with cell disruptor Pulverize, obtain target product.

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, described step 1) include walking as follows Rapid:

1.1) ethanol, ammoniacal liquor and deionized water are joined in single port flask, stir, the most dropwise instill positive silicic acid four The ethanol solution of ethyl ester (TEOS), under magnetic agitation, 30-40 DEG C is reacted 10-15 hour, is centrifuged off supernatant liquor, takes White solid, obtains Nano-meter SiO_2₂Microballoon (SNP).

1.2) by Nano-meter SiO_2₂Microballoon (SNP) joins in toluene, and ultrasonic disperse is subsequently adding gamma-aminopropyl-triethoxy Silane (APTES), 60-80 DEG C of magnetic agitation is reacted 15-20 hour, is centrifuged off supernatant liquor, obtains surface amino groups modification Nano-meter SiO_2₂Microballoon (SNP-NH₂)。

1.3) 4,4 '-azo double (4-cyanopentanoic acid) (ACPA) and I-hydroxybenzotriazole (HoBT) are dissolved in N, N-diformazan In base formamide (DMF), ice-water bath stirs, be subsequently adding the Nano-meter SiO_2 that surface amino groups is modified₂Microballoon (SNP- NH₂), ethyl [3-(dimethylamino) propyl group] carbodiimide hydrochloride (EDCI) and the mixed solution of triethylamine, under nitrogen protection, Ice-water bath reacts 1-1.5 hour, then normal-temperature reaction 18～24 hours, it is centrifuged off supernatant liquor, obtains intermediate 1 (SNP-ACPA)。

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, the Nano-meter SiO_2 that surface amino groups is modified₂ Microballoon with the mass ratio of 4,4'-azo double (4-cyanopentanoic acid) is: 1:0.5-1；Preferably 1:0.7.

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, described step 2) include walking as follows Rapid: N-caprolactam (NVCL) is dissolved in Isosorbide-5-Nitrae-dioxane, it is subsequently adding intermediate 1 (SNP-ACPA), Ultrasonic disperse, normal temperature leads to nitrogen gas stirring 20-40 minute, then heats to 70-80 DEG C, continues logical nitrogen 20-40 minute, so After add the Isosorbide-5-Nitrae-dioxane solution of mercaptoethanol, nitrogen protection lower reaction 20-25 hour, be centrifuged off supernatant liquor, Obtain intermediate 2 (SNP-g-PNVCL-OH).

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, N-caprolactam and sulfydryl second The mol ratio of alcohol is: 90-110:1；Preferably 100:1.

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, described step 3) include walking as follows Rapid: by Bis (ε-caprolactone-4-yl) (BCY), 6-caprolactone (CL), intermediate 2 (SNP-g-PNVCL-OH), Stannous octoate and dimethylbenzene mixing, ultrasonic disperse, vacuumize, and logical nitrogen then heats to 110-130 DEG C, under magnetic agitation React 45-50 hour, be centrifuged off supernatant liquor, obtain intermediate 3 (SNP-g-PNVCL-b-cPCL).

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, intermediate 2 and the quality of 6-caprolactone Ratio is: 1:5-10, preferably 1:5；6-caprolactone with the mass ratio of Bis (ε-caprolactone-4-yl) is: 5-10:1, preferably 10:1。

The preparation method of above-mentioned flexible polymer Janus nanometer sheet PNVCL/cPCL, the concentration expressed in percentage by volume of hydrofluoric acid is 10%-50%, preferably 40%.

Target product flexible polymer Janus nanometer sheet PNVCL/cPCL using the method for the present invention to prepare is nano-sheet knot Structure, side has hydrophilic poly-N-vinylcaprolactam, and opposite side has hydrophobic poly-epsilon-caprolactone.

The invention has the beneficial effects as follows: anchor azo-initiator at silicon ball surface, it is adaptable to cause any vinyl monomer to exist Silicon ball surface glycerol polymerization.Add chain-transferring agent mercaptoethanol, the nanometer of synthesis terminal hydroxy group poly-N-vinylcaprolactam grafting SiO₂Microballoon (SNP-g-PNVCL-OH) is applicable to any lactone that can cause ring-opening polymerisation with hydroxyl.Poly-for preparation flexibility Compound Janus nanometer sheet has universality.

The present invention, from the point of view of building-up process, at Nano-meter SiO_2₂Microsphere surface anchoring azo initiator and then trigger monomer occur certainly It is polymerized by base, mild condition, it is easy to operation, there is universality.ESEM and transmission electron microscope all demonstrate that this method is last and obtain To be flaky material, illustrate the feasibility of the method.

This flexible polymer Janus flaky material being made up of PNVCL/PCL, wherein side for have temperature sensitivity and Hydrophilic PNVCL, opposite side is hydrophobic PCL, utilizes this characteristic of material, by the control to temperature, control The wellability of Janus nanometer sheet PNVCL side processed, and then realize bag load and the release of medicine, PNVCL has life simultaneously Thing compatibility, PCL has biological degradability, to organism nonhazardous, so this flaky material is in fields such as medicine controlled delivery There is good application prospect.

Accompanying drawing explanation

Fig. 1 a is the Zeta potential figure of SNP.

Fig. 1 b is SNP-NH₂Zeta potential figure.

Fig. 2 is the infrared spectrogram of SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c).

Fig. 3 is the thermal gravimetric analysis curve figure of SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c).

Fig. 4 is that SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c), flexible polymer Janus receive The scanning electron microscope (SEM) photograph of rice sheet PNVCL/cPCL1 (d).

Fig. 5 is that SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c), flexible polymer Janus receive The transmission electron microscope picture of rice sheet PNVCL/cPCL1 (d).

Detailed description of the invention

The preparation of embodiment 1 flexible polymer Janus nanometer sheet PNVCL/cPCL1

(1) Nano-meter SiO_2 of terminal hydroxy group PNVCL grafting₂The synthesis of microballoon (SNP-g-PNVCL-OH)

1, mono-dispersed nano SiO₂The preparation of microballoon (SNP):

Use classicsMethod synthesis mono-dispersed nano SiO₂Microballoon (SNP).Preparation process is: by 42.6mL second Alcohol, 25mL ammoniacal liquor, 9.75mL deionized water join in 250mL single port flask, stir.Weigh the positive silicon of 7.7g Acid tetra-ethyl ester (TEOS), joins in the beaker filling 30mL ethanol, pours in constant pressure funnel after mixing, by Instilling in single port flask, lower 35 DEG C of magnetic agitation is reacted 12 hours.After having reacted, it is centrifuged off supernatant liquor, White solid.With ethanol: the white solid ultrasonic disperse that the mixed solution of water=9:1 (volume ratio) will obtain, then it is centrifuged Separate, take solid.Repeat this operation 3 times, obtain SNP 2.58g.Product is put into 50 DEG C of vacuum drying chambers, is dried 24 little Time, standby.Synthetic route is as follows:

2, Nano-meter SiO_2₂Modified (the SNP-NH of microballoon (SNP) surface amino groups₂):

1.5g SNP joins in 50mL dry toluene, ultrasonic until dispersion is complete.Take 0.8g gamma-aminopropyl-triethoxy silicon Alkane (APTES) joins in the mixed solution of SNP and toluene, and 70 DEG C of magnetic agitation are reacted 18 hours.Reaction completes After, it is centrifuged off supernatant liquor, then with toluene, solid is disperseed, then be centrifuged, repeat this operation three times, obtain 1.7g SNP- NH₂.Product is put into 50 DEG C of vacuum drying chambers, is dried 24 hours, standby.Synthetic route is as follows:

3, amino modified Nano-meter SiO_2₂Microballoon (SNP-NH₂) surface anchoring azo initiator (SNP-ACPA):

In 250mL there-necked flask, add 1.0g ACPA (4,4 '-azo is double (4-cyanopentanoic acid)) and 0.77g HoBT (1-hydroxy benzenes And triazole), dissolve with 50mL DMF, ice-water bath stirs.By 1.0g SNP-NH₂, 1.37g ethyl [3-(dimethylamino) Propyl group] carbodiimide hydrochloride (EDCI), 2.2mL triethylamine join in 250mL beaker, and ultrasonic disperse, by molten for this mixing Liquid joins in there-necked flask, under nitrogen protection, reacts 1 hour in ice-water bath, then normal-temperature reaction 18～24 hours.Reaction completes After, it being centrifuged off supernatant liquor, clean three times with DMF, deionized water is cleaned three times, obtains 1.1g SNP-ACPA.Will Product is put into 30 DEG C of vacuum drying chambers and is dried 24 hours, standby.Synthetic route is as follows:

4, the Nano-meter SiO_2 of terminal hydroxy group PNVCL grafting₂The synthesis of microballoon (SNP-g-PNVCL-OH)

In 50mL there-necked flask, add 5.0g N-caprolactam (NVCL), 30mL1,4-dioxane, be completely dissolved After, add 0.5g SNP-ACPA, ultrasonic until dispersion is complete, normal temperature leads to nitrogen gas stirring 30 minutes, is then warming up to 75 DEG C, continue logical nitrogen 30 minutes.Take 0.028g mercaptoethanol to be dissolved in the Isosorbide-5-Nitrae-dioxane of 1.0mL, inject with syringe In there-necked flask, the lower reaction of nitrogen protection 24 hours.After having reacted, it is centrifuged off supernatant liquor, clear with Isosorbide-5-Nitrae-dioxane Washing three times, oxolane cleans three times, obtains 1.2g SNP-g-PNVCL-OH, and putting into 50 DEG C of vacuum drying chambers, to be dried 24 little Time, standby.Synthetic route is as follows:

(2) Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂The synthesis of microballoon (SNP-g-PNVCL-b-cPCL1)

25mL eggplant-shape bottle adds 0.05g crosslinking agent B CY, 0.5mL 6-caprolactone (CL), 0.1g SNP-g-PNVCL- OH, 18mg stannous octoate, 15mL dimethylbenzene, ultrasonic until dispersion, carry out system three times vacuumizing completely-lead to nitrogen After, it is warming up to 120 DEG C, reacts 48 hours under magnetic agitation.After having reacted, centrifugal, remove supernatant liquor, use diformazan Benzene cleans three times, and oxolane cleans three times, obtains 0.21g SNP-g-PNVCL-b-cPCL1, puts into vacuum drying chamber, and 50 DEG C be dried 24 hours, standby.Synthetic route is as follows:

(3) flexible polymer Janus nanometer sheet PNVCL/cPCL1 is prepared

In 50mL polytetrafluoroethylene beaker, addition 0.05g SNP-g-PNVCL-b-cPCL1,20mL ultra-pure water, ultrasonic After dispersion completely, add the hydrofluoric acid of 10mL 40% under magnetic agitation, react 12 hours.Then it is centrifuged, removes supernatant Liquid, respectively cleans twice with water, ethanol respectively.Under the conditions of 4 DEG C, pulverized with cell disruptor, centrifugal, obtain 0.01g sheet-like flexible polymer Janus nanometer sheet PNVCL/cPCL1, is dried in vacuum drying chamber.The following institute of synthetic route Show:

(4) testing result

Under conditions of Fig. 1 a is pH=6, the Zeta potential figure of SNP, Fig. 1 b is SNP-NH₂Zeta potential figure.Modified Front Nano-meter SiO_2₂The Zeta potential of microballoon is-22.1mV, the Nano-meter SiO_2 after amino modified₂The Zeta potential of microballoon is 25.4mV, Zeta potential is by just bearing change.This is because when pH=6, Nano-meter SiO_2 before modified₂There is great amount of hydroxy group negative electricity on surface Property group, Zeta potential is negative, and the Nano-meter SiO_2 after amino modified₂A large amount of amino positive electricity group, Zeta are contained in surface Current potential is just.Amino modified Nano-meter SiO_2₂Zeta potential absolute value more than the absolute value of Zeta potential before modified, explanation Modified Nano-meter SiO_2₂Carried charge increases, and electrostatic repulsion increases, and dispersion stabilization also can significantly improve.

Fig. 2 is the infrared spectrogram of SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c).Wherein (a) For pure Nano-meter SiO_2₂The infrared spectrum of microballoon, 1100cm^-1And 800cm^-1Place belongs to the antisymmetric stretching vibration of Si-O-Si key And symmetrical stretching vibration, 471cm^-1Place belongs to the flexural vibrations of Si-O-Si key, and at above three, absworption peak is nanometer titanium dioxide The characteristic absorption peak of silicon.B () is the Nano-meter SiO_2 of terminal hydroxy group PNVCL grafting₂Microballoon (SNP-g-PNVCL-OH) infrared Spectrum, 2800-3000cm^-1Place is absorbed as C-H stretching vibration and absorbs, 1453cm^-1Locate to absorb for C-H flexural vibrations, say Bright PNVCL is successfully grafted to Nano-meter SiO_2₂Microsphere surface.C () is the Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Microballoon (SNP-g-PNVCL-b-cPCL) infrared spectrum, at 1733cm^-1Place is absorbed as carbonyl absorption on PCL chain, shows to gather N-caprolactam/Nano-meter SiO_2₂6-caprolactone ring-opening polymerisation is successfully caused on complex microsphere surface, obtains the poly-of outer layer crosslinking The Nano-meter SiO_2 of compound cladding₂Microballoon.

Fig. 3 is the thermal gravimetric analysis curve of SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c), bent Line (a) is pure Nano-meter SiO_2₂The thermogravimetric curve of microballoon, when temperature rises to 800 DEG C from room temperature, it loses weight and is 10.5%, the predominantly dehydration between water and the silanol of silicon ball surface absorption.Curve (b) is the nanometer of terminal hydroxy group PNVCL grafting SiO₂The thermogravimetric curve of microballoon (SNP-g-PNVCL-OH), loses the weight of 4.3% more, shows relative to curve (a) PNVCL-OH is successfully grafted to Nano-meter SiO_2₂Microsphere surface.Curve (c) is the Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Micro- The thermogravimetric curve of ball (SNP-g-PNVCL-b-cPCL), loses the weight of 2.7% more relative to (b), shows successfully to synthesize The Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Microballoon.

Fig. 4 is SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c), flexible Janus nanometer sheet (d) Scanning electron microscope (SEM) photograph.A () is pure Nano-meter SiO_2₂Microballoon, it is seen then that pass throughThe silicon ball size of method synthesis is homogeneous, its diameter For about 400nm, smooth surface.B () is the Nano-meter SiO_2 of terminal hydroxy group PNVCL grafting₂Microballoon (SNP-g-PNVCL- OH), (b) can significantly find out, silicon ball surface becomes coarse, and there is projection local, shows that the PNVCL of terminal hydroxy group becomes Merit receives silicon ball surface.C () is the Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Microballoon (SNP-g-PNVCL-b-cPCL), It will be seen that silicon ball surface is more coarse from figure, and ratio is more uniform, shows with the nanometer of terminal hydroxy group PNVCL grafting SiO₂Microballoon is initiator, under conditions of crosslinking agent B CY exists, successfully causes the crosslinking of polymerization limit, 6-caprolactone limit, is formed The Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Microballoon.D () is the Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Microballoon and hydrogen After fluoric acid effect, through low-temperature grinding, the flexible Janus nanometer sheet obtained.By (d) figure it can be seen that through hf etching and low Temperature obtains flaky material after pulverizing, and has certain thickness, and wherein side is hydrophilic PNVCL, and opposite side is hydrophobic friendship Connection PCL.

Fig. 5 is SNP (a), SNP-g-PNVCL-OH (b), SNP-g-PNVCL-b-cPCL (c), flexible Janus nanometer sheet (d) Transmission electron microscope picture.A () is pure Nano-meter SiO_2₂Microballoon, size is homogeneous, the smooth of the edge, and (b) is terminal hydroxy group PNVCL grafting Nano-meter SiO_2₂Microballoon (SNP-g-PNVCL-OH), can significantly be found out by (b), silicon ball edge is the most smooth, shows to hold hydroxyl The PNVCL of base the most successfully receives silicon ball surface.C () is the Nano-meter SiO_2 of the polymer overmold of outer layer crosslinking₂Microballoon (SNP-g- PNVCL-b-cPCL), it will be seen that the polymeric layer of silicon ball surface cladding is the most thickening from figure, and the most all Even, show that silicon bag is the most successfully covered by the PCL of crosslinking.D () is the Nano-meter SiO_2 of polymer overmold₂Microballoon is through hf etching After, the flaky material that low-temperature grinding obtains.

The preparation of embodiment 2 flexible polymer Janus nanometer sheet PNVCL/cPCL2

(1) Nano-meter SiO_2 of synthesis terminal hydroxy group PNVCL grafting₂Microballoon (SNP-g-PNVCL-OH): with embodiment 1.

(2) Nano-meter SiO_2 of the polymer overmold of synthesis outer layer crosslinking₂Microballoon (SNP-g-PNVCL-b-cPCL2):

25mL eggplant-shape bottle adds 0.1g crosslinking agent B CY, 1mL 6-caprolactone (CL), 0.1g SNP-g-PNVCL- OH, 18mg stannous octoate, 15mL dimethylbenzene, ultrasonic until dispersion completely, vacuumizes, logical nitrogen, repeats this operation three Secondary, then it is warming up to 120 DEG C, reacts 48 hours under magnetic agitation.After having reacted, centrifugal, remove supernatant liquor, use Dimethylbenzene cleans three times, and oxolane cleans three times, puts into vacuum drying chamber afterwards, and 50 DEG C are dried 24 hours.Product passes through SEM, TEM, TGA etc. confirm.

(3) flexible polymer Janus nanometer sheet PNVCL/cPCL2 is prepared: with embodiment 1.

The preparation of embodiment 3 flexible polymer Janus nanometer sheet PNVCL/cPCL3

(1) Nano-meter SiO_2 of synthesis terminal hydroxy group PNVCL grafting₂Microballoon (SNP-g-PNVCL-OH): with embodiment 1.

(2) Nano-meter SiO_2 of the polymer overmold of synthesis outer layer crosslinking₂Microballoon (SNP-g-PNVCL-b-cPCL3):

50mL eggplant-shape bottle adds 0.2g crosslinking agent B CY, 1mL 6-caprolactone (CL), 0.1g SNP-g-PNVCL- OH, 30mg stannous octoate, 30mL dimethylbenzene, ultrasonic until dispersion completely, vacuumizes, logical nitrogen, repeats this operation three Secondary, then it is warming up to 120 DEG C, reacts 48 hours under magnetic agitation.After having reacted, centrifugal, remove supernatant liquor, use Dimethylbenzene cleans three times, and oxolane cleans three times, puts into vacuum drying chamber afterwards, and 50 DEG C are dried 24 hours.Product passes through SEM, TEM, TGA etc. confirm.

(3) flexible polymer Janus nanometer sheet PNVCL/cPCL3 is prepared: with embodiment 1.

From the point of view of building-up process, at Nano-meter SiO_2₂Microsphere surface anchoring azo initiator and then trigger monomer generation radical polymerization Close, mild condition, it is easy to operation, there is universality.What ESEM and transmission electron microscope all demonstrated that this method finally obtains is Flaky material, illustrates the feasibility of the method.This flexible polymer Janus sheet material being made up of PNVCL/PCL Material, owing to it has temperature sensitivity, biocompatibility and biological degradability, has well in fields such as medicine controlled delivery Application prospect.

Claims (6)

1. the preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL, it is characterised in that comprise the steps:

1) with Nano-meter SiO_2₂Microballoon is hard template, anchors azo-initiator 4 at silicon ball surface, double (the 4-cyano group penta of 4'-azo Acid), obtain intermediate 1；Particularly as follows:

1.1) ethanol, ammoniacal liquor and deionized water are joined in single port flask, stir, the most dropwise instill positive silicic acid tetrem The ethanol solution of ester, under magnetic agitation, 30-40 DEG C is reacted 10-15 hour, is centrifuged off supernatant liquor, takes white Look solid, obtains Nano-meter SiO_2₂Microballoon；

1.2) by Nano-meter SiO_2₂Microballoon joins in toluene, ultrasonic disperse, is subsequently adding gamma-aminopropyl-triethoxy-silane, 60- 80 DEG C of magnetic agitation are reacted 15-20 hour, are centrifuged off supernatant liquor, obtain the Nano-meter SiO_2 that surface amino groups is modified₂ Microballoon；

1.3) 4,4 '-azo double (4-cyanopentanoic acid) and I-hydroxybenzotriazole are dissolved in DMF, in ice-water bath Stir, be subsequently adding the Nano-meter SiO_2 that surface amino groups is modified₂Microballoon, ethyl [3-(dimethylamino) propyl group] carbon two Inferior amine salt hydrochlorate and the mixed solution of triethylamine, under nitrogen protection, react 1-1.5 hour in ice-water bath, then normal temperature React 18～24 hours, be centrifuged off supernatant, obtain intermediate 1；

2) with intermediate 1 as initiator, mercaptoethanol is chain-transferring agent, causes the polymerization of N-caprolactam, obtains middle Body 2；Particularly as follows: be dissolved in Isosorbide-5-Nitrae-dioxane by N-caprolactam, it is subsequently adding intermediate 1, ultrasonic Dispersion, normal temperature leads to nitrogen gas stirring 20-40 minute, then heats to 70-80 DEG C, continues logical nitrogen 20-40 minute, Then Isosorbide-5-Nitrae-the dioxane solution of mercaptoethanol is added, nitrogen protection lower reaction 20-25 hour, it is centrifuged off Clear liquid, obtains intermediate 2；

3) with 6-caprolactone as monomer, intermediate 2 is initiator, and stannous octoate is catalyst, Bis (ε-caprolactone-4-yl) For crosslinking agent, obtain intermediate 3；Particularly as follows: by Bis (ε-caprolactone-4-yl), 6-caprolactone, intermediate 2, Stannous octoate and dimethylbenzene mixing, ultrasonic disperse, vacuumize, and logical nitrogen then heats to 110-130 DEG C, magnetic Power stirring lower reaction 45-50 hour, is centrifuged off supernatant, obtains intermediate 3；

4) by intermediate 3 hf etching, at 0-5 DEG C, pulverize with cell disruptor, obtain target product.

The preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL the most according to claim 1, its feature exists In: the Nano-meter SiO_2 that surface amino groups is modified₂Microballoon with the mass ratio of 4,4'-azo double (4-cyanopentanoic acid) is: 1:0.5-1.

The preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL the most according to claim 1, its feature exists In: N-caprolactam with the mol ratio of mercaptoethanol is: 90-110:1.

The preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL the most according to claim 1, its feature exists In: intermediate 2 with the mass ratio of 6-caprolactone is: 1:5-10；6-caprolactone and the matter of Bis (ε-caprolactone-4-yl) Amount ratio is: 5-10:1.

The preparation method of flexible polymer Janus nanometer sheet PNVCL/cPCL the most according to claim 1, its feature exists In: the concentration expressed in percentage by volume of hydrofluoric acid is 10%-50%.

6., according to the preparation method of arbitrary described flexible polymer Janus nanometer sheet PNVCL/cPCL of claim 1-5, it is special Levy and be: target product flexible polymer Janus nanometer sheet PNVCL/cPCL of preparation is flaky nanometer structure, side Having hydrophilic poly-N-vinylcaprolactam, opposite side has hydrophobic poly-epsilon-caprolactone.