Figure 4.

(a) Example of a section of a network at rest, made of 30 conjugated polymer chains, each consisting of 146 segments (MW = 380,000 g/mol). The size of the network section is about 150 nm, and its average mesh size is 20 nm. (b) Image of the measured steady state jet profile and corresponding jet radius a vs axial position z (continuous line). The modeled polymer network radius, a_p vs z, is also shown (dashed line), together with the network mesh (viewed mesh density is diluted ×300 in each direction). The maximal jet radius is larger than the needle internal radius, a₀ = 96 μm, due to wetting of the needle face. Electric field = 1.8 kV/cm, flow rate = 10 μL/min, MEH-PPV volume fraction ϕ = 0.025.