ON THE STABILITY OF THE ALEXANDER POLYMER BRUSH

We present a Lagrangian description of the deformations. of flat Alexa nder polymer brushes. An Alexander brush is one in which all polymer c hains are stretched from the base to the free surface of the brush. We analyze the linear stability of a grafted brush and a symmetric diblo ck lamella in a melt state. Both systems are unstable against plane-wa ve surface deformations of short wavelengths. Stability can be recover ed with the introduction of a small but finite surface tension.