Of course, you can use polymers of different molecular weight.  Nevertheless,  you have to consider that viscosity is related with molecular weight,  so you will get different diameters for the fibers obtained for the same parameters such as voltage,  distance, etc.

Electrospinning is sensitive to almost all parameters you can change, so maybe indeed you'll see an effect on the final material. But the technique is also very flexible, therefore you can use blends of different molecular weights. Where will be the optimum, I don't know ...

Alain

If you seek a specific fiber diameter, then I think that blending of polymers with different molecular weights ought not be done. Electrospinning depends on viscosity & viscosity depends on the average molecular weight of the polymer. The final product is also dependent upon whether high or low or a mix of both polymeric material has been used. As you know, the higher the molcular weight of a polymer the more difficult is  its fabrication (into fibers, films, membranes...etc.).

Yes you can, but you will achieve different kinds of nanofibres (from higher molecular weight thicker fibres) and likelly not the same number of finer and thicker fibres on the surface. Herewith, you will need to find technological parameters (distance between electrodes and voltage) which allows to manufacture both kinds of fibres.

I agree with the previous answers. About the degradation of the material, polymers with lower molecular weights degrade faster then the ones with higher. What I expect is that the resistance of the fibers to mechanical stresses will be lower. How this will affect the whole membrane is hard to predict.

I would only do this if you're having trouble spinning fibers from the low MW polymer alone, since the high MW polymer will add plasticity to the sol gel and make it spinnable. Otherwise, just go with a single MW and adjust concentration and other spinning parameters to obtain fibers of a desired diameter.

As other researchers said, it's ok and you can use blend of two or more type of molecular weight of the same polymer for electrospining. But, it should be mentioned that the electrospining process dependent on two type of parameters: hydrodynamic and electrical parameters. Using different molecular weight of the same polymer in nanofiber production process has notable effect on nanofiber characteristic. The lower molecular weight, the faster degradation rate. Regarding to have better uniformity in nanofiber structure, the complete homogenization of polymer with different molecular weight is needed. 

Certainly, you can utilize polymers with different molecular weight. That will effect on solution viscosity, solution concentration and fibre diameter.

Based on my own experience in spinning of acrylic fiber, the spinning process not only depends on the molecular weight of the polymer but it also depends on molecular weight distribution (polydispersity). By mixing two different Mw polymers you can obtain your desired molecular weight but you broadened the molecular weight distribution. 

 Syeda, in our lab we only use the Mv weight as a guideline for polymer chain length (technically the viscosity of a resultant solution), which we compare to literature values to decide which polymer Mv to order, or which amount to use. When weighing out the polymer to create a sol-gel, we typically use w/v (weight of polymer to volume of solvent) or w/w (weight of polymer to weight of solution).