Nano grafting technology
Nano-graft reaction is to combine nano-particles and modifiers through chemical reaction to change the surface structure and state of nano-particles to achieve the purpose of surface denaturation. Nano-grafting technology occupies an extremely important position in the surface modification of nano-particles. Due to the fact that nano particles are larger than its surface area, the surface bond state and electronic state are different from the interior of the particles, and the incomplete coordination leads to the existence of a large number of bonding groups, which also provides favorable conditions for surface modification of nanoparticles. Surface chemical modification methods can be roughly divided into
1. Coupling agents: Inorganic nanoparticles are generally incompatible with organic materials commonly used for surface modification, so usually the help of coupling agent is required. Coupling agents usually require two functional groups that can react with the surface of nanoparticles and can react with organic modifiers. For instance, as of organo-silane (XR-Si (OR) 3), X is an organic functional group, one of the most representative types of coupling agents.
2. Esterification: The reaction between nanoparticles and alcohols is an esterification reaction. The esterification reaction can change the hydrophilic and hydrophobic properties of the surface of nanoparticles.
3.Polymerization graft modification: The use of chemical polymerization to graft polymers to the surface of nanoparticles to achieve the purpose of surface modification. The polymerization grafting method can be divided into.
(1) The initiator initiates the direct polymerization of monomers into polymer chains on the surface of nanoparticles.
(2) The use of chemical reactions to link polymer links to the surface of the particles.
The surface modification method can effectively improve or change the dispersion, weather resistance, durability and surface activity of nanoparticles, so that nanoparticles can produce new physical, chemical and optical properties to adapt to different application requirements.