Abstract:

To effectively prevent Escherichia coli in the air from attaching to food and other surfaces which causes intestinal diseases such as diarrhea in humans and animals, the electret film made of polytetrafluoroethylene was used as the test material, and the effects of negatively and positively charged electret film on E. coli were measured by the method of combining the controlled variates with theoretical analysis and experimental research. The results showed that the negatively charged electret film had an inhibitory effect on the normal growth of E. coli, with a maximum inhibition rate of 70.82%; the positively charged electret film promoted the growth of E. coli with a maximum promotion rate of 54.65%. It was further observed with an optical microscope that the colonies of E. coli treated under the positively electret film grew densely, while that treated under the negatively charged electret film sparsely grew. The main mechanism that the electret film influencing the growth of E. coli was that the electrostatic field affected the membrane potential of E. coli molecules, which then affected the growth of E. coli. The negatively charged electret film has a good inhibitory effect on E. coli and the study could provide a theoretical basis for producing materials related to electret sterilization.

Key words: electret, Escherichia coli, control variates, electrostatic effect, fractal growth