Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Potential profile in electrolyte
Posted 21.06.2015, 01:55 GMT-4 Low-Frequency Electromagnetics, Electrochemistry Version 4.4 1 Reply
Please login with a confirmed email address before reporting spam
Hi everyone,
I have a system of electrolyte (500nm in width) in contact with a thin insulator (SiO2-40nm). I want to apply a potential Vapp at one end of electrolyte and V=0 at another end of insulator(not the interface). Now the potential profile should be like - there is some drop near the Vapp end due to double layer formation then constant potential(not necesarily 0V) in bulk and finally drops to 0V in the insulator.
My problem is when I apply Poisson-Boltzmann (PB) or Modified PB, I get error for high Vapp (2V). And when apply low Vapp (0.2V), the entire potential drop (to 0V) in electrolyte only.
What I want is some non-zero potential at electrolyte/insulator interface which finally drops to 0V in insulator.
Hope you get my problem. Can someone help me.
Thanks & regards
Anup Kumar
I have a system of electrolyte (500nm in width) in contact with a thin insulator (SiO2-40nm). I want to apply a potential Vapp at one end of electrolyte and V=0 at another end of insulator(not the interface). Now the potential profile should be like - there is some drop near the Vapp end due to double layer formation then constant potential(not necesarily 0V) in bulk and finally drops to 0V in the insulator.
My problem is when I apply Poisson-Boltzmann (PB) or Modified PB, I get error for high Vapp (2V). And when apply low Vapp (0.2V), the entire potential drop (to 0V) in electrolyte only.
What I want is some non-zero potential at electrolyte/insulator interface which finally drops to 0V in insulator.
Hope you get my problem. Can someone help me.
Thanks & regards
Anup Kumar
1 Reply Last Post 22.06.2015, 04:35 GMT-4
Please login with a confirmed email address before reporting spam
Posted:
9 years ago
The electrolyte concentration should be very low in order to see a potential profile in the solution. SiO2 is an insulator, so you'll have a linear potential profile across it.
The source term is space zharge density: in water -2*rhoq*sinh(f*u) and in SiO2 zero. The diffusion coefficient is the permittivity of the medium.
Since you are using version 4.4. I cannot attach the model but its report in PDF. There you can see how it works.
br
Lasse
The source term is space zharge density: in water -2*rhoq*sinh(f*u) and in SiO2 zero. The diffusion coefficient is the permittivity of the medium.
Since you are using version 4.4. I cannot attach the model but its report in PDF. There you can see how it works.
br
Lasse
Attachments: