This Materials World Network project is a combined theoretical and experimental study of novel polymer films which contain block copolymer micelles (BCMs) whose micellar structure will be designed to respond to external stimuli. The project brings together an international team of researcher-theoreticians from the Department of Physics at Moscow State University, Russia (MSU) with their expertise in polymer theory, and a research group at Stevens Institute of Technology (US) with their expertise in synthesis, self-assembly and characterization of thin polymer films at surfaces. The use of stimuli-responsive BCMs, whose cores can be used to carry cargo, in combination with layer-by-layer (LbL) self-assembly is a new approach which is explored in this project. BCM-containing multilayers are able to carry and release large amounts of functional molecules in response to temperature or pH variations. The Russian group develops novel theoretical strategies based on weak and strong segregation approaches, a theory of reversible association-dissociation and a Random Phase Approximation (RPA) method to elucidate the structure of BCM in BCM/polyelectrolyte multilayer (PEM) films. The US group (1) synthesizes novel pH- and temperature-responsive block copolymers which contain zwitterionic groups in the micellar corona, (2) studies self-assembly of BCMs of these copolymers with a linear polyelectrolyte using LbL approach and (3) characterizes micellar structure and morphology in self-assembled films before and after application of environmental stimuli. In situ phase modulated ellipsometry and neutron reflectivity are applied to access the structure and molecular conformations in micelle-containing films. In situ ATR-FTIR and in situ AFM measurements also allow local ionization changes within the film and the strength of intermolecular binding and chain relaxations to be related to film morphology and response. The research yields guidelines for the construction of BCM/PEM films and, in a broader sense, reveals major polymer structure-property relationships as applied to polymer self-assembly at surfaces. The development of BCM/PEM materials will meet a yet unmet need for environmentally triggerable polymer films which, through changes in their structure, can efficiently regulate the delivery of drugs, cosmetic compounds or fragrances.
A significant feature of this collaboration is strong emphasis on education and exchange of faculty personnel and graduate students between the Russian and US labs. Visits of graduate students to MSU with the purpose of integrating theoretical and experimental knowledge of responsive BCM/PEM films in an international setting, exchange of teaching practices, enhancement of an international student exchange by participation of US students in an annual Student Conference on polymers and polymer films in Russia are planned. The US group will further disseminate the knowledge obtained during international exposure to undergraduate and high-school students.
This award is co-funded with the Office of International Science and Engineering. .
