Low-foaming nonionic Gemini surfactants are widely used in industrial cleaning and photoresist development. In this study

three low-foaming nonionic Gemini surfactants are synthesized by using 2

5-di-tert-pentylbenzene-1

4-diol and ethylene oxide as raw materials via ring-opening reaction under alkali-catalyzed conditions. The surfactants

named P1

P2

and P3

have different polyoxyethylene chain lengths of 6

7

and 8

respectively. The surface tension

critical micelle concentration (CMC)

wettability

emulsifying

and foaming properties of the three Gemini nonionic surfactants are carefully investigated. The surface tension of P1

P2

and P3 decreases with increasing concentration and remains unchanged when CMC is reached. While at the same concentration

the surface tension increases with the increase of polyoxymethylene chain length due to increased hydrophilicity. The CMC of P1

P2

and P3 are 1.225 mmol/L

1.016 mmol/L

and 0.70 mmol/L respectively

decreasing with the increment of polyoxymethylene chain length. The contact angle of P1

P2

and P3 decreases with increasing concentration and remains unchanged when the concentration is higher than CMC. The contact angle increases with the increase of polyoxymethylene chain length at the same concentration. The emulsion stability of P1

P2

and P3 increases with increasing concentration and it increases with the increasement of the polyoxyethylene chain length at the same time. The initial foaming volume of P1

P2

and P3 increases with increasing concentration and the chain length of polyoxymethylene at the same concentration. In particular

P1 has the lowest initial foaming volume

which is one percent of the conventional nonionic surfactant Tween-80

exhibiting excellent low-foaming properties. P2 and P3 also show good low-foaming ability

with less than 20% of the foaming ability of conventional surfactant Tween-80. Overall

the three Gemini surfactants offer excellent low-foaming properties while reducing surface tension

making them well-suited for real-world applications such as industrial cleaning and developer fluids.