A structural X-ray study on semifluorinated alkanes (SFA): SFA revisited

We present an X-ray scattering study on a series of semifluorinated n-alkan e (F12Hn) powder samples, with even-numbered hydrocarbon chains n = 6-18. A t elevated temperatures the samples appear to have a simple lamellar struct ure consisting of single-layered stacks. At ambient temperature three diffe rent rather complex bulk structures were observed as a function of the chai n length of the hydrocarbon molecular moiety. Our results are compared to s tructure models for F12Hn found in the literature, and some new features of the structure of the room temperature phase are disclosed.