Biomedical subjects

A Subbotin

Publications and source records attributed to A Subbotin.

3 recordsLinked to original sources

PubMed2006

Spontaneous bending of 2D molecular bottle-brush.

Using a scaling approach we consider a 2D comb copolymer brush under bending deformations. We show that the rectilinear brush is locally stable and can be characterized by a persistence length lambda increasing with the molecular weight of grafting side chains as lambda approximately M3. A bending instability due to redistribution of the side chains appears in the non-linear regime where bending is strong. Arguments are presented that the brush conformations consist of alternating rectilinear and bent sections corresponding to the different free-energy minima.

Computer Simulation↗

PubMed2003

Phase behavior and structure formation of hairy-rod supramolecules.

Phase behavior and microstructure formation of rod and coil molecules, which can associate to form hairy-rod polymeric supramolecules, are addressed theoretically. Association induces considerable compatibility enhancement between the rod and coil molecules and various microscopically ordered structures can appear in the compatibility region. The equilibria between microphase-separated states, the coil-rich isotropic liquid and the rod-rich nematic are discussed in detail. In the regime where hairy-rod supramolecules with a high grafting density appear as a result of the association, three phase diagram types are possible depending on the value of the association energy. In the low grafting density regime only the lamellar microstructure is proven to be stable.

Journal Article↗

PubMed2001

Strongly adsorbed comb copolymers with rigid side chains.

We study the conformational behavior in a plane of a comb copolymer molecule, consisting of a semiflexible backbone and rigid side chains interacting via a van der Waals potential. Using a mean-field approach, two different regimes are distinguished depending on the strength of the attraction between the side chains. In the weak attraction limit the side chains are oriented preferably perpendicular to the backbone. The persistence length lambda of the comb copolymer molecule scales as the second power of the length of the side chain L: lambda is proportional to L2. In the strong attraction limit all side chains become strongly tilted and the persistence length scales as lambda is proportional to L4. The nonlinear bending regime is also studied and characterized by a change in structure and a decreasing moment of bending force as a function of curvature, i.e., bending becomes easier.

Journal Article↗