The Challenge 

Croda wanted to test for effective coverage of TiO₂ powder after different coating steps.  Knowing that TiO₂ and the different coating materials each possess a unique surface charge, and so zeta potential, it was postulated that the effectiveness of a given coating could be determined by measuring changes in the zeta potential.

What We Delivered 

Lucideon (then Ceram) performed zeta potential vs pH measurements on (i) uncoated TiO₂ samples and then (ii) samples that had undergone different coating regimes associated with adding the first coating, second coating and so forth.  After each coating process, the zeta vs pH profile changed dramatically, with the degree of change proven to be a good measure of “quality of coverage”.  Testing also showed that each layer was being chemically attached to the previous layer to create a multilayer coating on the TiO₂ particle.

Value to the Client 

Using zeta potential vs pH analysis, Lucideon and Croda were able to (i) demonstrate when 100% coating coverage had been achieved at each coating stage (key for the generation of a reliable high grade TiO₂ powder) and (ii) avoid unnecessary material costs associated with applying too thick a layer at each stage.

It also showed that the layers were attached to the previous layer and also showed the coating had a high degree of integrity on the base TiO₂.