1. My problem is that I need the values produced by the module for the left and right hand limits approaching y=1.5 to be close so that the overall function in the module, namely n*\[Epsilon]grad(phi), is continuous across the border I have defined in my geometry.
2. Okay no worries thank you for trying to help!

For me it is by no means clear what you want to achieve. You could multipy your 1st expression by 3.9 and the 2nd by 43.6 and then they are close indeed, but I doubt that is an appropriate solution.

I assume that you have to regions in space. In one you have pot1, and in the other you have pot2. You could connect them from points short off the boundary by a polynomial so that the derivatives are equal. Is it this what you want to do?

p[x_] := Sum[a[i] x^i, {i, 0, 3}]

Solve[
 {
  p[x - d] == u phi[x - d],
  p[x + d] == v phi[x + d],
  D[p[x - d], x] == u (phi[x - d] - phi[x - d - eps])/eps,
  D[p[x + d], x] == D[p[x - d], x]
  },
 {a[0], a[1], a[2], a[3]}
 ]