Compression of finite size polymer brushes

We consider edge effects in grafted polymer layers under compression. For a semi-infinite brush, the penetration depth of edge effects xi proportional to h(0)(h(0)/h)(1/2) is larger than the natural height h(0) and the actual height h. For a brush of finite lateral size S (width of a stripe or radiu s of a disk), the lateral extension u(S) of the border chains follows the s caling law u(S) = xi phi(S/xi). The scaling function phi(x) is estimated wi thin the framework of a local Flory theory for stripe-shaped grafting surfa ces. For small x, phi(x) decays as a power law in agreement with simple arg uments. The effective Line tension and the variation with compression heigh t of the force applied on the brush are also calculated.