METHOD FOR PREPARING INVERSE OPAL COLLOIDAL CRYSTAL FIBERS

Abstract

The present invention discloses a method for preparing inverse opal photonic crystal fibers. In this method, by means of vertical deposition of colloidal spheres (micron scale or nanoscale), of polystyrene shell-core structured spheres and silica particles, the inverse opal colloidal crystal fiber stripes having a length of about 3.5 cm as well as an adjustable width and thickness is obtained. The invention provides a convenient method and achieves inverse opal photonic crystal fiber stripes with a high yield and a controllable size, and there is no crack on the surface of the fibers or inside the fibers. Furthermore, the inverse opal photonic crystal stripes of the invention can be peeled off from the surface of a glass slide and used conveniently.

Claims

1. A method for preparing non-crack inverse opal colloidal crystal fibers, comprising steps of: (1) forming a layer of a copolymer of methyl methacrylate (MMA) and acrylic acid (AA) on the surface of polystyrene (St) microspheres by a microemulsion method, to obtain shell-core structured P-(St-MMA-AA) microspheres with a polystyrene core; (2) uniformly mixing a 0.3%-1.0% w/v dispersion solution of the shell-core structured P-(St-MMA-AA) microspheres with silica nanoparticles by a weight ratio of 1:0.4-0.6 to form a colloidal solution, and obtaining colloidal crystal fiber stripes after vertical deposition of the colloidal solution and drying the colloidal solution in an oven under 50 C.; and (3) sintering the colloidal crystal fiber stripes in an oven under 500 C. for 2 hrs to remove the shell-core structured P-(St-MMA-AA) microspheres, to get the inverse opal colloidal crystal fibers, wherein the silica nanoparticles are irregular solid particles, and have a refractive index of 1.56; wherein the inverse opal colloidal crystal fibers have a length of about 3.5 cm and a width of 50 m-200 m; and wherein the inverse opal colloidal crystal fibers do not have crack on surface and in interior thereof.

2. The method as claimed in claim 1, wherein in the step (1), 2 ml methyl methacrylate, 2 ml acrylic acid, 38 ml polystyrene, 200 ml deionized water, 0-0.033 g sodium dodecyl sulfate (SDS), and 1 g sodium bicarbonate are added to a flask and stirred uniformly, then 2 ml of an ammonium persulfate solution is added after stirring under 70 C. for 0.5 h, subsequently the temperature is raised to 80 C. to continue the reaction under stirring for 10 hrs to generate the shell-core structured P-(St-MMA-AA) microspheres.

3. The method as claimed in claim 1, wherein in the step (2), the dispersion solution of the shell-core structured P-(St-MMA-AA) microspheres are prepared from the shell-core structured P-(St-MMA-AA) microspheres.

4. The method as claimed in claim 3, wherein the average size of the silica nanoparticles is 10-20 nm in the colloidal solution.

5. The method as claimed in claim 3, wherein in the step (2), a 0.4%-0.6% w/v dispersion solution of the shell-core structured P-(St-MMA-AA) microspheres and the silica nanoparticles are mixed uniformly by a weight ratio of 1:0.4-0.6 to form the colloidal solution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a flow diagram of a method for preparing inverse opal colloidal crystal fibers of the present invention;

[0020] FIG. 2 shows the structural color from the inverse opal photonic stripes of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The invention will be further illustrated in more detail with reference to accompanying drawings. It is noted that, the following embodiments only are intended for purposes of illustration and are not intended to limit the scope of the invention.

[0022] Referring to the FIG. 1, a method for preparing inverse opal photonic crystal fibers comprises the following steps:

[0023] (1) forming a layer of the copolymer of methyl methacrylate (MMA) and acrylic acid (AA) on the surface of polystyrene (St) microspheres by a microemulsion method, to obtain shell-core structured P-(St-MMA-AA) microspheres with a polystyrene core;

[0024] (2) uniformly mixing a 0.3%-1.0% w/v dispersion solution of the P-(St-MMA-AA) microspheres with silica sol nanospheres by a weight ratio of 1:0.3-0.6 to form a colloidal solution, and obtaining the colloidal crystal stripes after vertical deposition of the P-(St-MMA-AA) microspheres and the silica nanospheres and drying in an oven under 50 C.; and

[0025] (3) sintering the colloidal crystal stripes in an oven under 500 C. for 2 hrs to remove the P-(St-MMA-AA) microspheres, to get the inverse opal photonic crystal fiber.

[0026] Specifically, in the step (1), 2 ml methyl methacrylate, 2 ml acrylic acid, 38 ml polystyrene, 200 ml deionized water, 0-0.033 g sodium dodecyl sulfate (SDS), and 1 g sodium bicarbonate are added to a flask and stirred uniformly, then 2 ml of an ammonium persulfate solution is added after stirring under 70 C. for 0.5 h, subsequently the temperature is raised to 80 C. to continue the reaction under stirring for 10 hrs to generate the P-(St-MMA-AA) microspheres having a size of 190-450 nm.

Embodiment 1

[0027] 60 mg P-(St-MMA-AA) microspheres with a particle size of 190 nm and 18 mg silica particles were prepared into 20 ml dispersion solution with a 0.3% w/v of P-(St-MMA-AA) microspheres, wherein the weight ratio of P-(St-MMA-AA) microspheres and silica sol is 1:0.3. The dispersion solution was placed into a 25 ml beaker, after being uniformly mixed by ultrasonic, and then dried in an oven under 50 C. to give colloidal crystal stripes. The colloidal crystal stripes were sintered in an oven under 500 C. for 2 hrs to remove the P-(St-MMA-AA) microspheres, and inverse opal structured photonic crystal stripes were formed.

Embodiment 2

[0028] 80 mg P-(St-MMA-AA) microspheres with a particle size of 300 nm and 32 mg silica particles were prepared into 20 ml dispersion solution with a 0.4% w/v of P-(St-MMA-AA) microspheres, wherein the weight ratio of P-(St-MMA-AA) microspheres and silica sol is 1:0.4. The dispersion solution was placed into a 25 ml beaker, after being uniformly mixed by ultrasonic, then was dried in an oven under 50 C. to give colloidal crystal stripes. The colloidal crystal stripes were sintered in an oven under 500 C. for 2 hrs to remove the P-(St-MMA-AA) microspheres, and inverse opal structured photonic crystal stripes were formed.

Embodiment 3

[0029] 100 mg P-(St-MMA-AA) microspheres with a particle size of 400 nm and 50 mg silica particles were prepared into 20 ml dispersion solution with a 0.5% w/v of P-(St-MMA-AA) microspheres, wherein the weight ratio of P-(St-MMA-AA) microspheres and silica sol is 1:0.5. The dispersion solution was placed into a 25 ml beaker, after being uniformly mixed by ultrasonic, then was dried in an oven under 50 C. to give colloidal crystal stripes. The colloidal crystal stripes were sintered in an oven under 500 C. for 2 hrs to remove the P-(St-MMA-AA) microspheres, and inverse opal structured photonic crystal stripes were formed.

Embodiment 4

[0030] 80 mg P-(St-MMA-AA) microspheres with a particle size of 448 nm and 48 mg silica particles were prepared into 20 ml dispersion solution with a 0.6% w/v of P-(St-MMA-AA) microspheres, wherein the weight ratio of P-(St-MMA-AA) microspheres and silica sol is 1:0.6. The dispersion solution was placed into a 25 ml beaker, after being uniformly mixed by ultrasonic, then was dried in an oven under 50 C. to give colloidal crystal stripes. The colloidal crystal stripes were sintered in an oven under 500 C. for 2 h to remove the P-(St-MMA-AA) microspheres, and inverse opal structured photonic crystal stripes were formed.

[0031] The silica particles in the above four embodiments are irregular solid particles, and have a size of 10-20 nm.

[0032] As shown in FIG. 2, the colloidal crystal stripes were prepared by vertical deposition of the P-(St-MMA-AA) microspheres and silica, and drying in an oven under 50 C. The colloidal crystal stripes have a length of about 3.5 cm and a width of 50 m-200 m. The colloidal crystal stripes were sintered in an oven under 500 C. for 2 hrs to remove the P-(St-MMA-AA) microspheres, and inverse opal structured photonic crystal stripes were obtained, wherein silica particles with a refractive index of 1.56 were filled in the gap of close-packed air spheres. Inverse opal structured photonic crystal stripes of different colors were obtained with P-(St-MMA-AA) microspheres of different sizes.

[0033] It can be seen from the above embodiments that, in the invention, when the dispersion solution has a 0.4%-0.6% w/v of P-(St-MMA-AA) microspheres of 300 nm, and the weight ratio of the P-(St-MMA-AA) microspheres and silica sol is 1:0.4-0.6, the obtained inverse opal structured photonic crystal stripes have the optimal length and width. In the invention, the P-(St-MMA-AA) microspheres of 300 nm are used, so that they can uniformly interact with the silica particles during the self-assembly via the vertical deposition, and the inverse opal colloidal crystal fibers are obtained without crack on its' surface and in its' interior, and the inverse opal colloidal crystal fibers can be peeled off from the surface of a glass slide and used conveniently.

[0034] The above preferred embodiments are described for illustration only, and are not intended to limit the scope of the invention. It should be understood, for a person skilled in the art, that various improvements or variations can be made therein without departing from the spirit and scope of the invention, and these improvements or variations should be covered within the protecting scope of the invention.