Electrospinning Coacervates – No Chain Entanglements Required

Electrospun fibers have utility across a range of fields. However, electrospinning traditionally requires long-chain, entangled polymer solutions. This combination of factors is necessary to create physical entanglements that relax slower than the timescale for electrospinning to prevent capillary breakup of the polymer jet. This requirement has also meant that spinning polyelectrolytes is particularly challenging as electrostatic repulsions along the polymer backbone dramatically increase the solution viscosity. We have reported a strategy for electrospinning charged polymers via complex coacervation. The coacervate liquid resulting from the complexation of oppositely-charged polymers can be used for electrospinning, resulting in solid fibers that are stable against dissolution in water and organic solvents. Here, we explore the potential for using the cooperative electrostatic interactions between polymer chains in place of physical entanglements. We investigated the electrospinnability of coacervates as a function of chain length. We demonstrated successful spinning of fibers using coacervates of oligomers of length <10. These results suggest the potential for using coacervates as a new class of electrospun materials where fiber formation is decoupled from chain length.