Estimate lamellae size in the symmetric diblock copolymer melt at $140C.$ Assume

that both blocks have identical Kuhn length $2\mathrm{.}0nm,$ repeat unit projection length

$0\mathrm{.}25nm,$ and repeat unit volume $0\mathrm{.}17n{m}^3.$ The surface free energy of the $A-B$

interface is $5\mathrm{.}0{10}^{-3}\frac{N}{m}.$