Hello sir

Thanks for your kind reply. Dielectric thickness is relatively high as compared to conventional EWOD devices. But, some literature reported PDMS based EWOD device with 35 micron of PDMS and 6mm/s average speed was achieved.

However, i did not think about the leakage through dielectric. Can you please let me know how to identify if leakage is happening and how to prevent them.

Hello sir

I did not see any noticeable change in contact angle upto 550 V and after that dielectric breakdown occurs. I will try to decrease the PDMS thickness.

Does sheet resistance play any role for EWOD actuation ?

Moreover, PDMS was mixed in 10:1 ratio followed by degassification and then it was cured at 75 degC for overnight. But still results in a slightly sticky nature. Slightly sticky nature may enhance the contact line pinning and frictional force terms around the three phase contact line of the droplet. No one around here have worked with PDMS. Can you please let me know that How does PDMS appear at the end of the process like it would be slightly sticky or perfectly smooth. something needs to change like mixing ratio or curing procedure?

Thanks

Are you sure that the base electrode (copper) is in contact with the PDMS substrate? It would be better to use an electrically conductive adhesive tape in order to bond them together.

Hi Nikolaos

Thanks for pointing out. Actuallh i am not sure about this. However, the PDMS is coated thorugh spin coater and it is supposed to spread all over the surface uniformly. But, i will also try with conductive adhesives tape.

But after tape, i am not sure if PDMS will spread over the surface uniformly.

Dear Mr. Ahmed,

In continuation with the aforementioned suggestions, I would suggest you to initially try using an Indium Titanium oxide coated glass, commonly known as ITO glass, for your experiments, instead of using copper as the base substrate. In our research with aluminum plate, as our base substrate, we too observed a greater value of the actuation voltage. Furthermore, what is the grade of the pdms that you are using? Is it from Dow or some where else. Kindly check the dielectric constant, and the Young's modulus of the pdms, and then go with the amount of crosslinker.

One last point, kindly check the working of the electrodes, as well.

Hope this helps.

Hi sir @sri Ganesh Subramanian

Thanks for your valuable suggestion. However, we are using PDMS Sylgard 184 but we are currently working towards Cr electrodes for better visualization as compared to ITO.

Thanks and Regards