The Polonaise appears to me to be in open, simple binary form. It begins with the A section in 3/4 (which it remains in throughout) and in the key of E major. A consists of a parallel, symmetric period that modulates in the second phrase group to the dominant major of B--thus making it "open" or "continuous". Both of the phrases in A end in a PAC, though the second PAC is naturally in B. For this reason, one may not choose to look at a as a parallel, antecedent-consequent phrase, but as a phrase group. However, givin that it is the A section of a clear binary form, I tend to look at it more as a parallel period. Immediately following, is the B section which begins in two four-measure phrases of developmental exploration in the key of c# minor. The first phrase of B especially echoes the theme of A in its onset, but does so in the minor key of c sharp. The consequent phrase from m13-16 does not resemble nearly as much the thematic content of A (there is one rhythmic gesture that reappears in the right hand of m 15). The two phrases represent a constrasting, symmetric period marked by a HC at measure 12 and by a PAC at measure 16. This is followed by a four measure transitional phrase where the theme of A is picked up again, but used to modulate back to BM, landing on an IAC. The last four measures consist of new expository material in the original key of E ending nicely on a PAC.
Because the B section not only does not clearly repeat the A section, but it has a long development and transitional area and also introduces new thematic material, I cannot see how this could be a rounded binary form. With A ending clearly in the dominant, and B standing very distinctly in contrast with A, I must dub this in open, simple binary form.