The influence of surface-active substances on the crystallization process and magnetic properties of goethite nanoparticles

To prevent the process of aggregation and growth of α-FeOOH nanoparticles, during chemical syntheses various surface-active substances (SASs) with a concentration of 3 g/dm$^3$ were added into the solution. The applied SASs were: cetylpyridinium chloride (CPC), sodium dodecyl sulphate (SDS), and complexone EDTA. Using various methods it was found that SAS molecules have a dual effect on the obtained nanoparticles: on one hand SAS application increases the number of small α-FeOOH nanoparticles with sizes of 2–5 nm. On the other hand, SAS molecules react with surface atoms of the nanoparticles and form additional compounds.