Carboxyl groups are weak acids. This means that with BGB Ultra™, you can change the behaviour of the CNC by changing pH.
At low pH, the carboxyl groups do not completely dissociate. This reduces the negative charge on the surface. The particles will clump together causing a higher hydrodynamic layer.
| | | |
|---|
| pH | Zeta Potential / mV
| Hydrodynamic Diameter / nm
|
|---|
| 3.12
| -22.53
| 1,597.0
|
|---|
| 4.76 | -26.37
| 159.0
|
|---|
| 6.41 | -30.07
| 140.4
|
|---|
| 7.26 | -30.03
| 138.3
|
|---|
| 8.66 | -31.17
| 141.6
|
|---|
| 9.77 | -34.47
| 141.9
|
|---|
This process is reversible. If you raise the pH, the negative surface charge increases and the hydrodynamic layer reduces to its original level.
