Extension of the wormlike bead-rod model (w = 4.6nm, lp = 53nm) in nanochannels of D1-by-D2 rectangular cross section. The geometric average of the channel size is Dav = (D1D2)1/2. Symbols are simulation data for three different contour lengths: L = 1.03μm for Dav = 30nm (diamond), L = 2.58μm for Dav = 60nm (square), and L = 4.12μm for Dav = 141.4nm (circle). Solid lines are smooth Bezier curves to approximate the data trend. The dashed line refers to predictions for the Odijk regime24,25 where we used Dav = 30nm, w = 4.6nm, and lp = 53nm.