Here are some things I’m going to talk about next week. It summarizes where I am in some of my thinking about dissertation research. If anyone wants to hear more and will be in Philadelphia, stop by!
Nanochemistry studies materials with at least one dimension in the nanoscale, usually defined as between 1-100 nm. Nanoscale materials display unusual optical, electromagnetic, and catalytic behaviors not observed in either molecular or macroscopic materials, such as surface plasmon resonance and quantum confinement. These behaviors can be tuned to perform in a wide variety of highly sensitive 21st-century technologies, including photovoltaics, biological labeling, digital displays, and drug delivery.
These behaviors are a product of nanoscale structural features of these materials, and most of the behaviors are influenced by the structure of a nanomaterial’s surface. Because a considerable fraction of the atoms in a nanomaterial belong to the surface layer of the material, surfaces in nanomaterials are unlike surfaces in macroscopic materials and so cannot be adequately described by standard models of macroscopic surfaces. Instead, aspects of both molecular and macroscopic theories are borrowed, with modifications, to form theoretical models of the structure and behavior of material surfaces at the nanoscale. This mixed-scale modeling is essential for proper characterization of nanoscale materials, and the resulting theoretical understanding of nanoscale surfaces suggests that standard philosophical accounts of theories and models in science fails to apply to nanoscience. I recommend a reconceptualization of modeling that focuses on information passage between scales. This method is influenced by Wilson’s and Batterman’s  recent suggestions for similar modeling strategies in physics, and I extend their suggestions in new directions.
This talk demonstrates the unusual relationship between surfaces, structure and behavior at the nanoscale by considering a class of nanomaterials known as anisotropic metal nanoparticles (AMNPs), which are monocrystalline metallic particles with well-defined morphologies such as cubes or triangular plates. These materials exhibit a behavior known as localized surface plasmon resonance (LSPR), which can be tuned by altering the size or shape of the particle to change its surface structure. Theoretical descriptions of AMNP surface structure 1) are highly sensitive to the scale of the system, 2) require multiple conflicting assumptions about the continuous and discrete nature of the material being modeled, and 3) rely heavily on mathematical structures that do not have clear physical analogs in the AMNP system. Most philosophical conceptions of relations between models at different scales fail to respect these features of nanoscale science. This talk argues that a more nuanced and sophisticated understanding of the role of models is required for an accurate understanding of nanoscale science.
 Mark Wilson (2010). “Mixed Level Explanation,” Philosophy of Science 77(5).
 Robert Batterman (2011). “The Tyranny of Scales,” forthcoming in the Oxford Handbook of Philosophy of Physics. Oxford Press.