NIRT: Nanometer Stoichiometric Particle Compound Solutions and Control of their Self-Assembly into the Condensed Phase

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National Science Foundation - Active Nanostructure and Nanosystems (ANN) (NSF 05-610)Nanoscale Interdisciplinary Research Teams (NIRT)ABSTRACTProposal Number: 0609318Principal Investigator: Sorenson, Christopher M.Affiliation: Kansas State UniversityProposal Title: NIRT: Nanometer Stoichiometric Particle Compound Solutions and Control of their Self-Assembly into the Condensed PhaseThis proposal was received in response to Nanoscale Science and Engineering initiative, NSF 05-610, category NIRT. The goal is to create a new family of nanometer "stoichiometric particle compounds," or what could also be called nanoparticles of all the same size, and to control their active assembly into condensed phases. In order to do this, understanding and control of solution phase and interfacial properties is needed. Understanding of particulate self-assembly to yield two and three dimensional superlattices, films and gels is also needed. To achieve this goal a series of nanomaterials will be synthesized in large amounts and will be "nanomachined" (digestively ripened) to molecular stoichiometry and stabilized with selected surface ligands. The ligands will be chosen for their tendencies to be hydrophobic or hydrophilic, their ability to form ordered monolayers, and to hydrogen bond and/or interdigitate with neighbors. In this way solution phase behavior, aggregation, crystallization to form superlattices, and assembly into various structures will be controlled. The physical chemistry of solutions, their phase diagrams, interfacial phenomena, and transitions to other phases is very well understood. Moreover, much is known about colloid phase stability and what happens when the colloid is destabilized. The new nanometer size stoichiometric particle compounds to be studied lie between solutions and colloids, and their phase behavior, interfacial phenomena, transitions to other phases, and controlled assembly have not been explored with experiment or theory. This research will attempt to rectify this lack of experimental data and understanding, and hence bind all these systems with one universal description. Therecently developed supramolecular building techniques will be extended to assembly of particles rather than molecules. The idea is to view these nearly uniform in size and composition nanoparticles as stoichiometric compounds with behavior, perhaps in some novel manner, analogous to "normal" atomic and molecular systems. Creation of materials based on single-sized nanoparticles, rather than atoms and molecules that actively assemble into superlattices, films, gels and supermolecular entities would yield a whole new class of materials with which it could rebuild or recreate all our modern marvels. Stoichiometric particle compounds can produce a particle-based world. Thus, from a broad perspective, this is an attempt to develop and then use the concept of a three-dimensional periodic table where size is the third dimension. The PIs will develop a streamlined set of course options to allow our students to achieve a broad training across physics, chemistry, materials science and engineering without significantly adding time to their training experience. The program will introduce teen women to nanoscience and technology through a recently established and very successful summer workshop series. The PIs will include undergraduates in the research year round.