A substance with surface activity is called a surface active substance.

2019-09-25 16:31:37

Surfactant characteristics, when a substance is added to a liquid, if it can reduce the surface tension, people call this substance has surface activity. Substances with surface activity are called surface active substances.

In terms of chemical structure, all surfactant molecules are composed of polar hydrophilic group and non-polar hydrophilic group. The hydrophilic group extends the molecule to the aqueous phase, while the hydrophilic group extends the molecule away from the aqueous phase to the oil phase, so the surfactant molecule is an amphiphilic molecule. Their hydrophilic groups are composed of alkyl groups, but their hydrophilic groups are various. Surfactants have great surface activity, so they are widely used in industrial and agricultural production and daily life for emulsification, dispersion, solubilization, wetting, foaming, washing, softening and other purposes.

The effect of nonionic surfactant aliphatic alcohol polyoxyethylene ether (AEO) on the colloid stability of water-based ink.

Non-ionic surfactants are more and more widely used because they do not exist in ionic state and are not easily affected by strong electrolytes. The effects of AEO-7 and AEO-9 on the stable average particle size and ZETA potential of water-based ink colloids were discussed.

ZETA potential curve showed that when AEO-7 concentration increased from 0 to 0.1 mol/L, ZETA potential changed from - 37.9 MV to - 16.3 mv. Because non-ionic surfactant has no charge, its adsorption on the surface of carbon black particles will not cause the change of its charge, but the negative charge on the surface of carbon black particles decreases when AEO-7 is added. The reason may be that AEO-7 adsorbed on the surface of carbon black particles makes the position of slip surface move or changes the solution. The average particle size curve shows that with the increase of AEO-7 concentration, the average particle size of carbon black increases from 154 nm to 240 nm, which indicates that the addition of AEO-7 may also reduce the steric hindrance effect between carbon black particles in water-based ink.

It can also be seen that AEO-7 not only has a great influence on the ZETA potential of the solution system, but also has a greater influence on the aggregation of carbon black particles than CTAB, SDS and CAPO. Fig. 6 shows the effect of different concentration of AEO-9 on the average particle size and Zeta potential of carbon black in water-based ink.

The influence of nonionic surfactants on the colloidal stability of water-based ink Zeta potential of water-based ink colloidal solution and the change trend of average particle size of carbon black after adding AEO-9 are the same as that after adding AEO-7.