Arrangement and method to apply diffusing wave spectroscopy to measure the properties of multi-phase systems, as well as the changes therein

Method for measuring physico-chemical properties of liquids such as solutions, dispersions and emulsions, comprising the steps of:

• producing a light beam (2)
• emitting light in a liquid (7);
• detecting said light after being scattered by said liquid (7);
• converting the detected light in an electrical signal;
• transmitting said electrical signal to processing means;
• calculating the autocorrelation function g(2) in the time- or the frequency domain of said electrical signal characterized in that said maximum value or the mean square displacement <Δrm2> is calculated from the autocorrelation function g(2)τ(r), or from g(2)(τ) in a similar way, as a function of time and the value of the physico-chemical property is calculated from said calculated maximum value of the mean square displacement <Δrm2>.

Method for measuring physico-chemical properties of liquids therein, such as solutions, dispersions and emulsions, comprising the steps of:

• producing a light beam (2)
• emitting light in a liquid (7);
• detecting said light after being scattered by said liquid (7);
• converting the detected light in an electrical signal;
• transmitting said electrical signal to processing means;
• calculating the autocorrelation function g(2) of said electrical signal, characterized in that the half decay time is calculated as a function of time or the autocorrelation function, and the value of the physico-chemical property is determined using a predetermined relation between the half decay time and the autocorrelation function.