For example, is there any material I can place over a capacitive sensor, or the finger or conductor approaching it, so that the sensor will no longer activate?
Electronic – ny material that obstructs or resists capacitive sensing
capacitiveresistance
Best Answer
A capacitive touch sensor sort of forms a parallel plate capacitor with your appendages. As capacitance increases above a threshold, the sensor triggers. So, let us examine the capacitance of a parallel plate capacitor and see what we can do to reduce it:
$$ C = \frac{k \epsilon_0 A}{d} $$
where \$ \epsilon_0\$ is the permittivity of space, a constant; \$ k\$ is the relative permittivity of the dielectric, dependent on the material between the two plates; \$A\$ is the area of the plates; and \$d\$ is the distance between them.
You can increase \$d\$ by a little bit by adding some material, but as you said in your comment, this alone is not enough.
\$A\$ is tricky to change; you don't want to modify the sensor, and your fingers aren't going to shrink.
It seems the obvious solution, then, is to reduce \$k\$. Unfortunately, as far as I am aware, \$k \simeq 1\$ for air, and all solids have \$k>1\$.
So, it seems like this is not possible.