Did you try it with petroleum ether? This exposed polymer can be destroy?

No Sir, I didn't try for petroleum ether. I'll try this in future. But I exposed Polyaniline to ammonia vapors and HCl vapors, it gave me doping and dedoping nature of Polyanilne respectively which I was willing to get.

Since the main composition of LPG are alkanes it should show a decrease in conductivity but the response is not that great as PANI sensor response depends on the polarity of the vapor and most alkanes are not extremely polar