Summary

From the thesis:

SUMMARY
Raspberry-like particles were made with spherical positively charged seed particles and spherical
negatively charged smaller particles. The attraction from the small particles onto the surface of
the seed particles is a heterocoagulation technique. It has been proven that it is essential that
the seed particles contains poly-N-isopropylacrylamide (pNIPAM) for the attraction between the
small particles and the large particles. The small particles make the surface of the raspberry-like
particles rough.
The coverage (the amount small particles onto the surface of the seed particles) was varied
through varying the salt concentration. It was conrmed that the coverage of the raspberry-like
particle increases with increasing salt concentration. The analyzes were done with a transmission
electron microscope (TEM) and with dynamic light scattering (DLS).
It has also been proven that the salt concentration can still in
uence the coverage after the forming of raspberry-like particles. This means that the dilutions before a measurement may not be performed with water. Water lowers the salt concentration and this decreases the coverage.
This is the reason that the samples have to be diluted with a salt concentration where
the raspberry-like particles are already in. Therefore, the raspberry-like particles keep the same
environment and this gives more reliable results for the analyzes.
An optimal sequence exists for adding small particles, seed particles and salt together. This
has to do with the moment when the small particles or seed particles comes in contact with a
certain salt concentration.