Macromolecular Theory and Simulations

Cover: A field-theoretic simulation is performed on the response of a loop-forming diblock copolymer film to pressure. Based on a compressible random-phase approximation in the spirit of the Ginzburg-Landau formalism, this method is capable of visualizing patterns inside the copolymer film in between selective surfaces at ambient conditions and also upon pressurization. Further details can be found in the article by J. Cho on page 8.

The pressure response of diblock copolymer films is investigated through a field-theoretic simulation based on a compressible random-phase approximation in the spirit of deterministic time-dependent Ginzburg-Landau formalism. The method is capable of visualizing patterns inside the pressurized copolymer films between selective surfaces, and can also provide a dynamic pathway toward those patterns.

The free energy penalty for a macromolecule entrapped in the spherical cavity of radius D is different for flexible and semiflexible chains both in its extent and in the respective scaling law. The resulting structural arrangements feature a globular and a toroidal structure, respectively.

A general and rigorous new formulation for the multicomponent copolymerization equation is presented based on matrix notation. The new formulation is explicit, easy to implement and introduces a natural scaling to the problem. It overcomes the computational limitations of the original W&B formulation and is general, as opposed to other specific formulations that have appeared in the literature.

A model is developed to simulate the response of polyacrylamide gel (PAG) dosimeters to a single spherical brachytherapy seeds using high-dose-rate (HDR) Ir¹⁹² and low-dose-rate (LDR) I¹²⁵ seeds. Results show that PAG dosimeters can provide accurate HDR brachytherapy dosimetry but will give poor results for LDR due to monomer diffusion.

ICAR ATRP of methyl methacrylate and styrene is studied as a function of the catalyst reactivity and reaction conditions. The concept of competitive activation/deactivation equilibria is successfully applied to formulate general guidelines allowing the optimization of ICAR processes.