We have reported a voltage–free pyroelectrification (PE) process able to induce permanent and 2D patterned dipoles into polymer films, thus producing freestanding bipolar membranes. A single thermal stimulus triggers simultaneously the glass transition and the dipole orientation in the polymer. The technique is surprisingly easy to accomplish since the polymer solution is simply spin–coated onto a pyroelectric lithium niobate crystal that, during the thermal stimulus, generates spontaneously a surface charge density strong enough to orient the polymer dipoles.
Contact person: Simonetta Grilli, ISASI Pozzuoli