You'll have the p*** taken massively (and correctly in my view!).
I can't think of a good reason for wearing them in a PPL environment other than as an ego massaging device.
Pitts2112 has given you the "rank" that the different bars mean, but as a PPL, you have as little right to wear them as you do to term yourself Captain away from the a/c.
In an airline, they are worn to denote rank since you have more than one member of a crew. In private flying, there is only one pilot, so obviously they are the "captain", so therefore there is no need for differentiation, since the only other people in the a/c are "passengers" and they certainly don't need to wear rank insignia.
Wear wings if you want,afterall you are a licenced pilot and have earned these, but airline insignia should be left to airline crews. Personally I have always taken off my bars as soon as I left the airport since to me they become meaningless away from the job.