CN101423614B - Luminescent fibre hydrogel and preparation method thereof - Google Patents

Abstract

The invention relates to a luminescent cellulose hydrogel and a preparation method thereof. The luminescent cellulose hydrogel is prepared by the following method: dissolving cellulose in NaOH with a mass percentage concentration of 6-10% and urea with a mass percentage concentration of 4-10%. In the aqueous solution of 12% NaOH/urea, obtain the NaOH/urea combined aqueous solution that dissolves cellulose, the mass percentage concentration of cellulose in the combined aqueous solution is 1～6%, then be 10 by the molar ratio of cellulose and quantum dot: Add CdSe/ZnS quantum dots with a size of 2 to 7nm, a concentration of 0.1μM to 200μM, and carboxyl groups on the surface at a ratio of 1 to 1000:1, and finally add the required amount of crosslinking agent epichlorohydrin to chemically crosslink React and place at gel temperature until luminescent cellulose hydrogel is formed. This luminescent cellulose hydrogel can be widely used in fields such as optical devices, biomedicine, and controlled release of drugs.

Description

Luminescent cellulose hydrogel and preparation method thereof

technical field

The invention relates to a luminescent cellulose hydrogel and a preparation method thereof, belonging to the field of polymer materials.

Background technique

Plant cellulose is the most abundant renewable resource on earth, and cellulose materials can be decomposed by microorganisms after being discarded, which is an environmentally friendly material. No use or generation of harmful substances, and the use of renewable resources to produce environmentally friendly materials is a frontier field in the world today. Recently, the preparation and application of hydrogels have developed rapidly, and many advantages such as water absorption, environmental sensitivity, water retention, and biocompatibility have attracted much attention, especially the preparation of quantum dot-based luminescent hydrogels. extensive attention of researchers. However, the current luminescent hydrogels have only been reported based on synthetic polymers, and no reports have been found on cellulose-based luminescent hydrogels. However, due to the poor biodegradability of synthetic polymer hydrogels, its production and application are greatly limited.

Contents of the invention

The purpose of the present invention is to provide a luminescent cellulose hydrogel and its preparation method, because the preparation method of the luminescent cellulose hydrogel is simple and fast, the raw material cost is low, and the whole process is pollution-free, so the obtained product has better biocompatibility and biodegradability. This biodegradable cellulose luminescent hydrogel can be widely used in the fields of optical devices, biomedicine, controlled release of drugs and the like.

The technical solution adopted to realize the object of the present invention is that the luminescent cellulose hydrogel is prepared by the following method: dissolving cellulose in NaOH/urea with a concentration of 6-10% by mass of NaOH and a concentration of 4-12% by mass of urea. In the aqueous solution, obtain the NaOH/urea combination aqueous solution that dissolves cellulose, the mass percent concentration of cellulose in the combined aqueous solution is 1～6%, and then according to the molar ratio of cellulose and quantum dot is the ratio of 10:1～1000:1 Add CdSe/ZnS quantum dots with a size of 2-7nm, a concentration of 0.1μM-200μM, and carboxyl groups on the surface, and finally add the required amount of cross-linking agent epichlorohydrin, undergo chemical cross-linking reaction, and place at gel temperature Until the luminescent cellulose hydrogel is formed, the viscosity-average molecular weight of the cellulose used is in the range of 30,000 to 100,000.

Compared with the prior art, the present invention has the following advantages:

The invention uses natural polymer cellulose as raw material, and the dissolving process is very simple, fast and pollution-free. The cellulose and quantum dots are uniformly mixed, and the cross-linking reaction is very rapid, and the temperature requirement is not high, which is conducive to industrial production, and the waste liquid is easy to recycle and reuse. The invention uses sodium hydroxide, urea and water as raw materials, has low price, is simple and convenient to operate, and has no pollution to the environment. This is a significant technical advance over previous methods.

Detailed ways

The technical scheme of the present invention will be further described below in conjunction with specific examples:

Example 1

Disperse 0.4 g of cellulose (viscosity-average molecular weight Mη=3.5×10 ⁴ ) in 9.6 g of a mixed aqueous solution containing 6wt% NaOH and 4wt% urea, pre-cool to -20~-10°C, thaw after 5~24 hours and stir A transparent cellulose solution was obtained, and the concentration of the cellulose solution was 2 wt%. Mix 100 μl of CdSe/ZnS quantum dots with a carboxyl group on the surface with a concentration of 17.9 μM and a size of 3.4 nm with the cellulose solution, then add 1 ml of epichlorohydrin dropwise to the mixed solution, and heat up to the gel temperature of 60 °C , after 0.5 hours, a cellulose hydrogel emitting red light under an ultraviolet lamp was obtained. The formed luminescent cellulose hydrogel was washed repeatedly with distilled water to remove residual NaOH, urea and cross-linking agent epichlorohydrin.

Example 2

Disperse 0.3 g of cellulose (viscosity-average molecular weight M _η =3.5×10 ⁴ ) in 9.7 g of a mixed aqueous solution containing 8wt% NaOH and 10wt% urea, pre-cool to -20 to -10°C, and thaw after 5 to 24 hours Stir to obtain a transparent cellulose solution with a concentration of 3 wt%. Mix 100μl of quantum dots with a concentration of 10.8μM and a size of 3nm with the cellulose solution evenly, add 0.8ml of epichlorohydrin dropwise to the mixed solution, raise the temperature to a gel temperature of 50°C, and obtain a gel after 2 hours. Cellulose hydrogel that emits yellow-green light. The formed luminescent cellulose hydrogel was washed repeatedly with distilled water to remove residual NaOH, urea and cross-linking agent epichlorohydrin. The CdSe/ZnS quantum dots used are core-shell structures with carboxylated surfaces and negative charges.

Example 3

Disperse 0.2 g of cellulose (viscosity-average molecular weight M _η =3.5×10 ⁴ ) in 9.8 g of a mixed aqueous solution containing 6wt% NaOH and 4wt% urea, pre-cool to -20 to -10°C, and thaw after 5 to 24 hours Stir to obtain a transparent cellulose solution with a concentration of 2 wt%. Mix 100 μl of quantum dots with a concentration of 29.12 μM and a size of 3.1 nm with the cellulose solution evenly. 0.5 ml of epichlorohydrin was added dropwise into the mixed solution, and the temperature was raised to 30° C. After 12 hours, a cellulose hydrogel emitting yellow light under an ultraviolet lamp was obtained. The formed luminescent cellulose hydrogel was washed repeatedly with distilled water to remove residual NaOH, urea and cross-linking agent epichlorohydrin.

Example 4

Disperse 0.3 g of cellulose (viscosity-average molecular weight M _η =3.5×10 ⁴ ) in 9.7 g of a mixed aqueous solution containing 8wt% NaOH and 10wt% urea, pre-cool to -20 to -10°C, and thaw after 5 to 24 hours Stir to obtain a transparent cellulose solution with a concentration of 2 wt%. Mix 100 μl of quantum dots with a concentration of 136.93 μM and a size of 2.8 nm with the cellulose solution evenly. 0.5ml of epichlorohydrin was added dropwise into the mixed solution, and the temperature was raised to 80°C. After 0.5 hours, a cellulose hydrogel emitting green light under an ultraviolet lamp was obtained. The formed luminescent cellulose hydrogel was washed repeatedly with distilled water to remove residual NaOH, urea and cross-linking agent epichlorohydrin.

The luminescent cellulose hydrogel prepared by the invention does not emit light under visible light, but the luminescent cellulose hydrogel prepared under different conditions under ultraviolet light can emit light of various colors respectively.

Claims (8)

1. A luminescent cellulose hydrogel, characterized in that it is prepared by the following method: dissolving cellulose in an aqueous solution of NaOH/urea with a concentration of 6 to 10% by mass of NaOH and a concentration of 4 to 12% by mass of urea , to obtain the NaOH/urea combined aqueous solution having cellulose dissolved, the mass percent concentration of cellulose in the combined aqueous solution is 1 to 6%, and then the molar ratio of cellulose to quantum dots is 10:1 to 1000:1. CdSe/ZnS quantum dots with a concentration of 2-7nm and a concentration of 0.1 μM to 200 μM, and with carboxyl groups on the surface, and finally add the required amount of cross-linking agent epichlorohydrin, undergo a chemical cross-linking reaction, and place it at the gel temperature until To form a luminous cellulose hydrogel, the viscosity-average molecular weight of the cellulose used ranges from 30,000 to 100,000. 2. The preparation method of the luminescent cellulose hydrogel according to claim 1, characterized in that the specific preparation steps are: dissolving cellulose in NaOH with a mass percentage concentration of 6-10%, and urea with a mass percentage concentration of 4-12% In the aqueous solution of NaOH/urea, obtain the NaOH/urea combination aqueous solution that dissolves cellulose, the mass percent concentration of cellulose in the combination aqueous solution is 1～6%, then be 10:1～by the molar ratio of cellulose and quantum dot Add CdSe/ZnS quantum dots with a size of 2-7nm, a concentration of 0.1μM-200μM, and carboxyl groups on the surface at a ratio of 1000:1, and finally add the required amount of cross-linking agent epichlorohydrin, through chemical cross-linking reaction, Leave at gel temperature until luminescent cellulose hydrogels are formed. 3. The preparation method of luminescent cellulose hydrogel according to claim 2, characterized in that: after adding cellulose to the combined aqueous solution of NaOH/urea and stirring, then freezing at -10 to -20°C for 5 to 24 hours , then thawed and stirred to obtain an aqueous NaOH/urea combination solution in which cellulose was dissolved. 4. The preparation method of luminescent cellulose hydrogel according to claim 2, characterized in that: the CdSe/ZnS quantum dots used have a core-shell structure, the surface is carboxylated, and presents a negative charge. 5. The preparation method of luminescent cellulose hydrogel according to claim 2, characterized in that: the ratio of the amount of epichlorohydrin used to the solution before adding epichlorohydrin is 0.1-1.5ml/10g, and Add epichlorohydrin dropwise to the solution. 6. The preparation method of luminescent cellulose hydrogel according to claim 2, characterized in that: the gelling temperature is 30-80°C. 7. The preparation method of luminescent cellulose hydrogel according to claim 2, characterized in that: the reaction time is 0.5-12 hours. 8. The preparation method of luminescent cellulose hydrogel according to claim 2, characterized in that: the formed luminescent cellulose hydrogel is repeatedly rinsed with distilled water to remove residual NaOH, urea and cross-linking agent.