“…A three-level fractional factorial linear screening design with three centre points was generated with the software package MODDE (v12.1, Sartorius Stedim Data Analytics AB, Umea, Sweden [62]). The range of the process variables was derived from literature [50,51,52,53,54,55,56,57,58], delimiting the design space with 4 variables set to quantitative (concentration of PVDF in spinning dope c PVDF 12–18 wt.%, concentration of PVP in spinning dope c PVP 4–6 wt.%, temperature of spinning dope T Dope 20 ∘normalC to 50 ∘normalC, and temperature of coagulation bath T H 2 O 20 ∘normalC to 50 ∘normalC) and 2 factors set to multilevel (MW PVDF 390, 585, 685 kDa and MW PVP 10, 55, 360 kDa). The generated screening design with 21 possible dope solutions is tabulated in Table 1.…”