Can you get pregnant if you ejaculate on a towel and your partner wipes herself with the towel after a shower a day later?

No. If you are ejaculating on a towel then you are a man, and men cannot get pregnant.

Nope! No chance at all! Sperm's mobility is impaired after a few minutes exposure to the air. It will be pretty much all done in within an hour even if it was in a semi liquid environment. No chance of surviving on a towel the following day! Towels, clothes, toilet paper, napkins, etc. all do what they are supposed to do; they absorb fluid. Semen on any of these surfaces will get absorbed and thus dry out. Once semen is dry the sperm, which live in semen, die as well.