A method of assembling silica particles on a cotton fabric

Abstract

A method for assembling silica particles on cotton fabric belongs to the field of textile printing and dyeing technology. The method is characterized by the following process: (1) Adding a certain amount of silica particles and polyethylene glycol diglycidyl ether to deionized water and stirring until homogeneous, allowing it to stand at room temperature for 10 minutes, then adding a certain amount of chitosan quaternary ammonium salt, adjusting the pH of the system to 10, and finally setting the concentrations of silica particles, polyethylene glycol diglycidyl ether, and chitosan quaternary ammonium salt to 5 g / L, 0.25 g / L, and 0.2 g / L respectively, reacting at 70°C for 30 minutes, centrifuging, and washing with water to obtain modified silica particles; (2) Assembling the cotton fabric: Step 1, preparing a 4 g / L dispersion of modified silica particles, adjusting the pH to 5, immersing the cotton fabric in the solution at a 100:1 bath ratio for 5 minutes, rinsing with deionized water, and drying; Step 2, preparing a 4 g / L dispersion of unmodified silica particles, adjusting the pH to 6, immersing the cotton fabric in the solution at a 100:1 bath ratio for 5 minutes. min, rinse with deionized water and dry; (3) The above two steps constitute one assembly cycle. Repeat the assembly cycle as needed to adjust the amount of silica assembled on the cotton fabric. Tests show that after the silica particles are modified by chitosan quaternary ammonium salt, they can be directly assembled on the cotton fabric and can drive the subsequent adsorption and assembly of unmodified silica particles. Through repeated cycles, the amount of silica assembled can be effectively increased.

Description

Technical Field

[0001] This invention relates to a method for assembling silica particles on cotton fabrics, belonging to the field of textile printing and dyeing technology. Background Technology

[0002] Currently, with the development of science and technology, the development and research of functional textiles has become a hot topic. Silicon-based materials, due to their ease of surface modification, high chemical stability, and rich functionality, show broad application prospects in the field of functional textiles. Silica is the most common silicon-based material, and when combined with textiles in appropriate ways such as dip coating, gravity / vertical deposition, vapor deposition, electrophoretic deposition, and electrostatic assembly, it can endow them with various functions such as self-cleaning, water repellency, UV protection, and antibacterial properties.

[0003] In recent years, electrostatic assembly technology has attracted researchers' attention due to its advantages such as simple operation and mild conditions. However, silica particles have a large number of hydroxyl groups on their surface, resulting in strong negative charge and strong electrostatic repulsion with fabrics such as cotton, linen, and polyester, leading to poor results in direct electrostatic assembly. To solve this problem, researchers have tried treating the fabric with positively charged substances such as cationic bovine serum albumin, polydiallyldimethylammonium chloride, and polyethyleneimine, and then adsorbing negatively charged silica particles, thus completing one assembly cycle. Through repeated assembly cycles, a silica coating of a certain thickness is eventually formed on the fabric. However, this method can only form one silica coating in each assembly cycle, resulting in low assembly efficiency. Summary of the Invention

[0004] This invention utilizes chitosan quaternary ammonium salt to modify silica particles. The modified silica particles can be directly assembled onto cotton fabrics and can drive the re-adsorption and assembly of subsequent unmodified silica particles, thereby completing one assembly cycle. Through repeated cycles, a silica coating of a certain thickness can be assembled on the fabric.

[0005] This invention mainly relates to the following processes: (1) Add a certain amount of silica particles and polyethylene glycol diglycidyl ether to deionized water and stir evenly. Let it stand at room temperature for 10 min. Then add a certain amount of chitosan quaternary ammonium salt and adjust the pH of the system to 10. The final concentrations of silica particles, polyethylene glycol diglycidyl ether and chitosan quaternary ammonium salt are 5 g / L, 0.25 g / L and 0.2 g / L, respectively. React at 70℃ for 30 min. After centrifugation and washing with water, modified silica particles are obtained. (2) Assemble the cotton fabric. Step 1: Prepare a 4 g / L dispersion of modified silica particles, adjust the pH to 5, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. Step 2: Prepare a 4 g / L dispersion of unmodified silica particles, adjust the pH to 6, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. (3) The above two steps constitute one assembly cycle. Repeat the assembly cycle as needed to adjust the amount of silica assembled on the cotton fabric.

[0006] A certain amount of silica particles and polyethylene glycol diglycidyl ether were added to deionized water and stirred until homogeneous. The mixture was allowed to stand at room temperature for 10 minutes. Then, a certain amount of chitosan quaternary ammonium salt was added, and the pH of the system was adjusted to 10. The final concentrations of silica particles, polyethylene glycol diglycidyl ether, and chitosan quaternary ammonium salt were 5 g / L, 0.25 g / L, and 0.2 g / L, respectively. The mixture was reacted at 70℃ for 30 minutes. After centrifugation and washing with water, modified silica particles were obtained. During this process, the chitosan quaternary ammonium salt was firmly bonded to the surface of the silica particles through electrostatic adsorption and cross-linking by polyethylene glycol diglycidyl ether. This not only imbued the surface with a positive charge but also prevented the chitosan quaternary ammonium salt from detaching during subsequent assembly, ensuring the stability of the dispersion and improving the assembly effect. The silica particles are conventional negatively charged silica, the chitosan quaternary ammonium salt is a commercially available product with a substitution degree of 98%, and the polyethylene glycol diglycidyl ether is a commercially available product with an epoxy value of 0.70-0.80 mol / 100g.

[0007] For assembling cotton fabric, the process involves two steps: First, a 4 g / L dispersion of modified silica particles is prepared, and the pH is adjusted to 5. The cotton fabric is then immersed in this dispersion at a 100:1 bath ratio for 5 minutes. Adjusting the pH to 5 ensures that the modified silica particles possess both high stability and a high positive charge. During this step, the modified silica particles spontaneously assemble onto the negatively charged surface of the cotton fabric through electrostatic attraction, forming the first assembled layer and simultaneously altering the surface charge of the cotton fabric. Second, a 4 g / L dispersion of unmodified silica particles is prepared, and the pH is adjusted to 6. The cotton fabric is then immersed in this dispersion at a 100:1 bath ratio for 5 minutes. Adjusting the pH to 6 ensures that the unmodified silica particles possess a certain degree of negative charge while minimizing the impact on the modified silica layer already assembled onto the fabric surface, thus ensuring the smooth implementation of subsequent assembly steps. In step two, electrostatic attraction occurs between the modified silica assembly layer on the fabric surface and the unmodified silica particles in the dispersion, driving them to adsorb and transfer to the fabric surface, thus forming a second silica assembly layer. These two steps constitute one assembly cycle. Different numbers of assembly cycles can be repeated as needed to continuously increase the amount of silica assembled. Detailed Implementation

[0008] The present invention will be further illustrated below with reference to examples and comparative examples.

[0009] Example 1 (1) Add a certain amount of silica particles and polyethylene glycol diglycidyl ether to deionized water and stir evenly. Let it stand at room temperature for 10 min. Then add a certain amount of chitosan quaternary ammonium salt and adjust the pH of the system to 10. The final concentrations of silica particles, polyethylene glycol diglycidyl ether and chitosan quaternary ammonium salt are 5 g / L, 0.25 g / L and 0.2 g / L, respectively. React at 70℃ for 30 min. After centrifugation and washing with water, modified silica particles are obtained. (2) Assemble the cotton fabric. Step 1: Prepare a 4 g / L dispersion of modified silica particles, adjust the pH to 5, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. Step 2: Prepare a 4 g / L dispersion of unmodified silica particles, adjust the pH to 6, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. (3) The above two steps constitute one assembly cycle. One, two and three assembly cycles are performed on the cotton fabric respectively.

[0010] Comparative Example 1 (1) Add a certain amount of silica particles and polyethylene glycol diglycidyl ether to deionized water and stir evenly. Let it stand at room temperature for 10 min. Then add a certain amount of chitosan quaternary ammonium salt and adjust the pH of the system to 10. The final concentrations of silica particles, polyethylene glycol diglycidyl ether and chitosan quaternary ammonium salt are 5 g / L, 0.25 g / L and 0.2 g / L, respectively. React at 70℃ for 30 min. After centrifugation and washing with water, modified silica particles are obtained. (2) Assemble the cotton fabric. Step 1: Prepare a 4 g / L dispersion of modified silica particles, adjust the pH to 5, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. Step 2: Prepare a 4 g / L dispersion of modified silica particles, adjust the pH to 5, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. (3) The above two steps constitute one assembly cycle. One, two and three assembly cycles are performed on the cotton fabric respectively.

[0011] Comparative Example 2 (1) Assemble the cotton fabric. Step 1: Prepare an unmodified silica particle dispersion of 4 g / L, adjust the pH to 6, immerse the cotton fabric in the dispersion at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. Step 2: Prepare an unmodified silica particle dispersion of 4 g / L, adjust the pH to 6, immerse the cotton fabric in the dispersion at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. (2) The above two steps constitute one assembly cycle. One, two and three assembly cycles are performed on the cotton fabric respectively.

[0012] Color tests were performed on the cotton fabrics obtained in Example 1, Comparative Example 1, and Comparative Example 2. The color L value was used to reflect the assembly of silica on the surface of the cotton fabric. The larger the L value, the greater the amount of silica assembled.

[0013] For Example 1, after 1, 2, and 3 assembly cycles, the L values ​​of the fabric surface were 15.99, 17.646, and 20.206, respectively. It can be seen that the L value of the fabric in Example 1 increased significantly after each assembly cycle (the L value of the fabric surface before silica assembly was 14.308), indicating that the amount of silica assembled continuously increased. Furthermore, the L values ​​of the fabrics obtained from the two steps of the first assembly cycle in Example 1 were measured to be 15.166 and 15.99, respectively, showing a significant difference, indicating effective silica assembly at each step. The L values ​​of the fabrics obtained from the two steps of the second assembly cycle in Example 1 were measured to be 16.61 and 17.646, respectively, showing a significant difference, indicating that effective silica assembly still occurred at each step. The L values ​​of the fabrics obtained from the two steps of the third assembly cycle in Example 1 were measured to be 18.946 and 20.206, respectively, still showing a large difference, reflecting that effective silica assembly still occurred at each step.

[0014] For Comparative Example 1, after 1, 2, and 3 assembly cycles, the L values ​​of the fabric surface were 15.366, 15.802, and 15.872, respectively. It can be seen that the L value of the fabric obtained in Comparative Example 1 increased significantly after the first assembly cycle (the L value of the fabric surface before silica assembly was 14.332), while the increase decreased significantly after the second and third assembly cycles. This indicates that the amount of silica assembled was relatively large only in the first cycle, with less assembly in subsequent cycles. Furthermore, the L values ​​of the fabrics obtained from the two steps of the first assembly cycle in Comparative Example 1 were measured, and were 15.28 and 15.366, respectively. The difference between the two was very small, indicating that a certain amount of silica was assembled only in step one, and the amount of silica assembled decreased significantly from step two onwards.

[0015] For Comparative Example 2, after 1, 2 and 3 assembly cycles, the L values ​​of the fabric surface were 14.898, 14.762 and 15.01, respectively. It can be seen that the L value of the fabric obtained in Comparative Example 2 did not increase significantly after assembly (the L value of the fabric surface before the assembly of silica was 14.512), indicating that it could not be effectively assembled on the fabric.

Claims

1. A method for assembling silica particles on cotton fabric, characterized in that... The following process is adopted: (1) Add a certain amount of silica particles and polyethylene glycol diglycidyl ether to deionized water and stir evenly. Let it stand at room temperature for 10 min. Then add a certain amount of chitosan quaternary ammonium salt and adjust the pH of the system to 10. The final concentrations of silica particles, polyethylene glycol diglycidyl ether and chitosan quaternary ammonium salt are 5 g / L, 0.25 g / L and 0.2 g / L, respectively. React at 70℃ for 30 min. After centrifugation and washing with water, modified silica particles are obtained. (2) Assemble the cotton fabric. Step 1: Prepare a 4 g / L dispersion of modified silica particles, adjust the pH to 5, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. Step 2: Prepare a 4 g / L dispersion of unmodified silica particles, adjust the pH to 6, immerse the cotton fabric in the solution at a bath ratio of 100:1 for 5 min, rinse with deionized water and dry. (3) The above two steps constitute one assembly cycle. Repeat the assembly cycle as needed to adjust the amount of silica assembled on the cotton fabric.