Dear all,
After my Fe3O4 nanoparticles were modified with TOES, the water dispersibility was thus greatly improved. But when I modified APTES on the surface of Fe3O4@SiO2, the water dispersibility of the nanoparticles became worse, why is that?
In addition to this, I am certain that APTES has been successfully modified on the surface of the nanoparticles due to the shift in zeta potential from negative to positive after coating. Fe3O4@SiO2@APTES is more readily dispersed in acidic solutions compared to neutral environments, which may also be an important feature for successful modification.
kind regards,
Lee.
Silane grafting on nanomaterials is an approach to decrease the hydrophilicity; so, your sample is more hydrophobic after APTES functionalization. The silane is able to react with hydroxyls of Fe3O4@SiO2, and therefore, the hydroxyl groups which are water-adsorbing sites are eliminated. Moreover, the nonpolar organic groups of the silane are decorated on the surface of the Fe3O4@SiO2, and therefore, the polar interaction sites with water are eliminated and hydrophilicity is reduced.
Sepideh Pourhashem Thank you for your reply! The Fe3O4@SiO2@APTES nanoparticles can disperse readily in the MES buffer (0.05 M, pH 5.5). However, it is difficult to disperse in the neutral solution, just like the PBS buffer (pH 7.4). What can I do to improve hydrophilicity of the Fe3O4@SiO2@APTES nanoparticles in the PBS buffer? Some people would further modify the surface of the nanoparticles by carboxylated dextran or others to facilitate hydrophilicity.
Thank you again for your help and sorry for the delay in my reply due to the time difference.
you are welcome. I am not sure which treatment will be useful for increasing the hydrophilicity of the Fe3O4@SiO2@APTES nanoparticles, but it seems acceptable to use an approach to increase the polar groups on their surface such as the methods you have mentioned (i.e. modifying the surface of the nanoparticles by carboxylated dextran or others). Wish you success in your research
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Carbon Materials
- Graphite
- Graphene