There are numerous hydroxyl groups and unsaturated remaining securities in various states on the outer layer of the silica nanoparticles, making the silica nanoparticles hydrophilic and oleophobic and simple to agglomerate. They should be practically adjusted to develop the execution and scope of utilizations further.
The surface modification of silica nanoparticles primarily focuses on the following three aspects:
Because surface-modified polystyrene nanoparticles can weaken the charging effect of surface-active hydroxyl groups and the hydrophilicity of surface groups, one is to improve or increase the dispersion between silica nanoparticles and their compatibility with other substances. As a result, it prevents particles from forming an aggregate or becoming compatible with organic substances;
The second option is to coat the surface of the silica with active groups in order to modify or enhance its surface activity and make it possible to graft further or functionalize nanoparticles;
The third is to expand the extent of the utilization of silica nanoparticles. New functions, such as drug delivery and release and stimulus responsiveness, can be produced by surface-modified nanoparticles.
Depending on whether the surface hydroxyl group and the modifier undergo a chemical reaction, silica nanoparticle surface modifications fall into two categories: chemical alteration and physical alteration. The chemical modification must alter the chemical properties of nanoparticles, whereas physical modification alters the ratio of hydroxyl groups on the surface of silica.
1. Physical modification of Silica nanoparticles The primary methods of physical modification of silica nanoparticles are adsorption, encapsulation, and coating with polymers or inorganic substances.
The surface testimony technique is the fundamental strategy for changing silica nanoparticles.
2. Surface chemical modification of silica nanoparticles is based on a chemical reaction between the modified molecules and many hydroxyl groups, or unsaturated bonds, on the particles' surface.