Electrokinetic sonic amplitude technique

Electroacoustic phenomena. They are electrokinetic phenomena that have recently gained interest, both experimentally and theoretically. In the ESA (electrokinetic sonic amplitude) technique, an alternating electric field is applied to the suspension and the sound wave produced in the system is detected and analyzed. The colloid vibration potential (CVP) or colloid vibration current (CVI) is the reciprocal of the former a mechanical (ultrasonic) wave is forced to propagate through the system, and the resulting alternating potential difference (or current) is measured. 

Because electrophoresis uses optical detection, this technique is limited to the analysis of dilute systems however, the recent development of electroacoustic methods has extended analysis to concentrated slurries containing up to 50% vol/vol solids [73], The electroacoustic effect is the response of charged particles to an applied alternating electrical or acoustical field [74], in contrast to the static field employed in electrophoresis. The acoustical response results from relative vibratory motion between particle and medium if the two phases differ in density. If an alternating electrical field is applied, charged particles vibrate in a back-and-forth motion in phase with the applied field, producing a sound wave whose pressure amplitude is proportional to the particle mobility and This technique is termed electrokinetic sonic amplitude (ESA). Alternatively, if an ultrasonic wave is applied, the particles vibrate at the sound... 

Electrokinetic sonic amplitude ESA, also termed electrosonic amplitude), an electro-acoustical method involving detection of the sound wave generated when dispersed species are made to move (oscillate) by an imposed alternating electric field (the principal features of the technique are shown in... 

Acoustics has a related field that is usually referred to as electroacoustics (8). Electroacoustics can provide particle size distribution as well as zeta potential. This relatively new technique is more complex than acoustics because an additional electric field is involved. As a result, both hardware and theory become more complicated. There are even two different versions of electroacoustics depending on what field is used as a driving force. Electrokinetic sonic amplitude (ESA) involves the generation of sound energy caused by the driving force of an applied electric field. Colloid vibration current (CVC) is the phenomenon where sound energy is applied to a system and a resultant eleetrie field or eurrent is created by the vibration of the colloid electric double layers. 

Similarly to LFDD, there is a set of electrokinetic techniques that involves ac fields and that can be applied to suspensions of arbitrary particle concentration, as they do not rely on optical techniques of evaluation. These are the so-called electroacoustic techniques, which enable the determination of the dynamic or ac mobility, u, of colloidal particles (the ac counterpart of the dc or classical electrophoretic mobility) as a function of frequency. There are basically two such techniques. One is based on the determination of the electric potential difference induced by the passage of a sound wave through the system it is called colloid vibration potential (CVP) or colloid vibration current (CVI), depending on the quantity measured. In the second technique, reciprocal of CVP or CVI, the basic process is the generation of a pressure wave when an ac electric field is applied to the suspension the amplitude of the sound wave, A sa is known as electrokinetic sonic amplitude, and so we speak of the ESA effect. After the very early works in the subject, O Brien [27,28] was the first author to perform a rigorous investigation on the physical foundations of electroacoustic techniques, and he found that Me is in fact proportional to [28] ... 

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