Particle potentiometric titration and particle size analyzer

Particle potentiometric titration and particle size analyzer

According to different measurement principles, there are electrophoresis and electroacoustic methodszetaPotential, andstabinoThe flow potential obtained from the test. These arezuiThe frequently mentioned potential parameter comes from the shear force acting on the ion cloud on the double layer at the particle interface, as shown in the figure1All these measured variables are related to the particle interface potential located on the shear plane（PIP）That iszetaThe potential is directly proportional. In order to establish the interface potential, either an electric field established by electrophoresis or electroacoustic methods, or mechanical stress applied to the flow potential and electroacoustic instruments, can be used. By doing so, external loosely attached ions from the solution are carried away, revealing an interface potential that can be directly measured.

Particle potentiometric titration and particle size analyzer

The purpose of potentiometric titration

According to different particle size ranges, it can be achieved throughSmoluchowski, Henry’sWaiting for formula calculationzetaElectric potential. To calculate correctlyzetaThe potential and particle size range require special attention. especially100nmWithin the following particle size range, regardingzetaThe correct calculation method of potential is still controversial in the academic community. It is also questionable whether obtaining a numerical value is necessary for reality. In addition, at a certain pointzetaThe potential value cannot clearly describe the entire sample system. The interface potential always depends on the ionic environment. Strictly speaking, without the ionic environment, the interface potential of particles cannot be discussed.

PHEven small changes in value can cause the pigment suspension to become unstable, despite its previouszetaThe potential is very high. Therefore, in-depth research is neededzetaThe titration curve of potential on titrants is very valuable. These titrants can be acidic or alkaline substances, ionic surfactants, or polyelectrolytes. Speaking of which, many valuable results can be obtained through potentiometric titration, some can be used to identify stable and unstable regions of suspensions, and some can be used to characterize the amount of coagulants or catalysts that cause polymerization or particle reactions.

Measure the potential of flowing current

By driving the piston to perform up and down reciprocating motion in the cylinder (as shown in the figure)2）The liquid in the gap between the cylinder wall and the piston will flow up and down. The shear force acting on the fixed particle interface can cause the ion cloud of the particles to transfer. These fixed particles are either due to the adhesion of large molecules or small particles to the vessel wall, or due to the inertness of large particles. In the calm area at the bottom of the sample, there is almost no displacement of ions. Therefore, oscillation signals at the bottom and higher parts of the cylinder can be obtained.

multi-functional

The particle size range applicable to the flow potential testing method indicates that the flow potential iszuiThe universal method,0.3nmThe macromolecular solution and300μmThe particle suspension or lotion can be measured by flowing potential method. The conductivity range allowed by this method is from zero to50mS/cmThe concentration range of the sample is from0.01to10vol%Or higher. The upper limit of viscosity is300mPasAt this viscosity, the effectiveness of mixing titrant into the sample is questionable. No other sample parameters are required except for the concentration of the sample and titrant.zuiHowever, equally important is that ifzetaPotential is very important, and in many applications, multiplying the flowing potential by a constant factor can be corrected tozetaElectric potential.

Efficient Application of Flowing Potential in Charge Titration

stabinoThe instrument has the functions of mixing, homogenization, and signal testing, making titration testing simpler and more effective. Typically, a typical titration cycle requires5-15minute.