How does a simple paper electroscope work?

(N/A) $1$. Take a strip of white paper and fold it in half to create a crease.
$2$. Open the strip and iron it lightly as shown in figure $(a)$ and $(b)$.
$3$. Hold the strip by pinching it at the fold. You will notice that the two halves move apart as shown in figure $(c)$.
$4$. This occurs because the process of ironing transfers charge to the paper strip.
$5$. Since both halves of the strip acquire the same type of charge,they exert an electrostatic force of repulsion on each other,causing them to move apart.