Molecular Switch Based on a Linear Macromolecule Inserted in a Second-Generation Dendron Brush

The behavior of a single linear chain inserted in a planar polymer brush made of second-generation dendrons grafted via their focal point has been theoretically studied using the Scheutjens–Fleer self-consistent field method. It has been shown that the linear macromolecule can undergo a conformational transition from the state of a “coil” located inside the brush to the state of a “flower” consisting of a strongly stretched stem immersed in the brush and a head located above the brush. This transition has features of a first-order phase transition. It can be provoked by increasing the length of the linear macromolecule, by increasing the grafting density, or by improving the quality of the solvent in which the brush is immersed. An increase the linear chain length lowers the height of the energy barrier separating the “coil” and “flower” states, but the transition itself occurs in a solvent of poorer quality. A new state of the linear chain under the poor solvent conditions, “flower in the brush,” when both the stem and the head of the flower are inside the brush, was discovered.