Colloidal Silica Modification

Introduction

Colloidal silica has the advantages of small particle size, large specific surface area, and good biocompatibility. As a nanomaterial, colloidal silica also has the advantages of surface interface effect and quantum size effect. They are widely used in rubber, coatings, plastics and biomedicine. However, its surface contains a large number of hydroxyl groups, which has strong hydrophilicity and is easy to agglomerate, which greatly limits the performance of colloidal silica. Therefore, modification is needed to further expand the application range of colloidal silica.^[1]

Fig. 1 Schematic illustration of hydrophobic modification of silica sols and aggregation of silica colloid particles^[2]

Alfa Chemistry's modification services for colloidal silica include:

• Physical Modification
  Alfa Chemistry can use physical modifiers such as surfactants, metal oxides and polymers to change the surface properties of colloidal silica through physical effects such as adsorption and coating, and finally achieve the purpose of reducing agglomeration and increasing dispersion stability.
• Chemical Modification
  Alfa Chemistry can provide a variety of chemical modification methods to reduce the hydrophilicity of colloidal materials by reacting chemical modifiers with hydroxyl groups on the surface of colloidal silica. Specific methods include silane coupling agent modification, fatty alcohol modification, polymer graft modification, in-situ modification, and the like. Among them, in-situ modification can complete the modification in the preparation process of colloidal silica, which is currently the most concerned method by customers.

Fig.2 Illustration of the surface modification of silica nanoparticle by APTMS followed by treatment with (a) RITC to measure the absorption and (b) methyl acrylate and ethylenediamine to increase the number of amine sites.^[3]

How we do?

• Alfa Chemistry provides one-stop service from preparation to modification of colloidal silica.
• Alfa Chemistry signed a cooperation agreement with customers to jointly develop new modified colloidal silica.
• Alfa Chemistry provides technical guidance for the modification of colloidal silica and helps customers develop new products.

References

1. Bo Chen, et al. Research progress of nano-silica surface modification. Silicone Material. 2006.
2. Huanjun Chang, et al. Facile Preparation of Stable Superhydrophobic Coatings on Wood Surfaces using Silica-Polymer Nanocomposites. Bioresources. 2015, 10(2).
3. Jung H S, et al. Quantitative Analysis and Efficient Surface Modification of Silica Nanoparticles. Journal of Nanomaterials. 2012.

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