Abstract: A method for manufacturing of porous polymer structures, in particular membranes, the method comprising the steps of providing a mixture of one or more polymers and one or more salt nano- and/or microparticles, primary shaping said blend, and removing said one or more salt particles, wherein at least part of the one or more salt nano- and/or microparticles is one or more solid acids, and whereby the ratio of polymer-to-particle is in the range of 3:1 to 1:10 by weight. Also provided are mixtures suitable to obtain such porous polymer structures, porous polymer structures as described herein, shaped articles containing such structures, and the use of such porous polymer structures, shaped articles and mixtures.