Effects of the homopolymer molecular weight on a diblock copolymer in a 3D spherical confinement.

The morphologies of a diblock copolymer spherically confined within a homopolymer were investigated by using the static self-consistent field theory method. A homogeneous - diblock copolymer sphere was surrounded by a homopolymer . Upon changing the diblock volume fraction, homopolymer molecular weight and the interaction between the copolymer and its surrounding environment, different morphologies of the sphere were observed.

First principles studies of an Si tip on an Si(100)2 × 1 reconstructed surface.

We present a systematic study of the interaction between a silicon tip and a reconstructed Si(100)2 × 1 surface by means of total energy calculations using density functional theory. We perform geometry optimization to obtain the reconstructed Si surface using the local density approximation and the generalized gradient approximation methods and compare our results with those obtained experimentally. We then study the effects of the tip of a scanning probe of an atomic force microscope (AFM) on the behaviour of atoms on the reconstructed surface when the tip translates at distances close to it.