UMass Amherst

2013 SURE Projects

Professor Ryan Hayward Polymer Science & Engineering
A. Responsive Polymer Nanostructures
Our group is working to create polymer surfaces that can be dynamically reconfigured to change their structure and properties. We study mechanical instabilities of responsive polymer gels as a route to reversibly generate topographic and chemical patterns on nanometer to micrometer length-scales. We are currently working on developing systems that can be triggered with magnetic and electric fields or illumination with light.
Professor Richard Vachet Chemistry
B. Environmental Impact of Nanoparticles
Nanomaterials are present in an increasing number of commercial products, and their release into the environment is inevitable. We are developing tools that provide insight into how nanoparticle (NP) properties influence their environmental fate, transport, bioaccumulation, and bioavailability. We are using gold NPs (AuNPs) and laser desorption/ionization mass spectrometry (LDI-MS) as tools to quantitatively answer questions related to environmental bioavailability. Unlike materials used in most previous environmental studies of NPs, AuNPs do not readily decompose and can be designed to have well-defined physical (e.g. size, charge) and chemical (e.g. hydrophobicity) properties. AuNPs also have photophysical properties that allow multiple particles types to be tracked simultaneously in the cells and tissues of plants and fish using LDI-MS. A student involved in this project will obtain experience with NP synthesis, mass spectrometry, and environmental chemistry.
Professor Bryan Coughlin Polymer Science & Engineering
C. Polymer Templates for Organic-based Photovoltaics
In a photovoltaic cell, photons are absorbed by a chromophore and create excited electron-hole pairs (excitons). Typical exciton diffusion distances are of the order of 5-20 nm. Therefore, in order to efficiently harvest electrons and holes, the separation distance between the conducting or semi- conducting elements, the p/n junction, must less than 20 nm. Block copolymers, two chemically different polymers joined together at one end, microphase separate into arrays of domains comparable to the dimension of the polymer chain (~ 10 nm in size). The Coughlin research group is developing nanoporous templates derived from block copolymers that will be used for the assembly of photovoltaics.
Professor Harry Bermudez Polymer Science & Engineering
D. Properties of Nanoscale DNA Structures
Below a critical length, DNA becomes a rigid molecule, enabling its use a nanoscale construction material.  Furthermore, the specificity of base-pairing allows for specific two and three-dimensional designs.  However, our understanding of the assembly process, its efficiency, and overall stability is far from complete.  This project would involve design and assembly of DNA structures followed by characterization with electrophoresis and fluorescence techniques.
Professor Alejandro Lopez Briseno Polymer Science & Engineering
E. Organic and Polymer Single-Crystalline Solar Cells
This project will focus on four areas where organic/polymer single-crystalline films will enable one to acquire a fundamental understanding of the photogenerated and transport processes at organic-organic interfaces and make the connection to applied science by demonstrating unconventional devices from single crystals. The four areas are: 1) single crystal bilayer solar cells, 2) single crystal nanowire heterojunction solar cells, 3) single crystal integrated chip, and 4) stretchable and wavy organic crystals. The intrinsic properties extracted from an all-organic crystal device structure will enable detailed analysis to be carried out in areas that have been difficult to study in bilayer and bulk heterojunction devices.
Professor Alejandro Lopez Briseno Polymer Science & Engineering
F. Polymers for use in Thermoelectric Energy Harvesting
Polymers are ideal for thermoelectric applications due to their intrinsically inefficient thermal conductivities; however, they suffer from low electrical conductivity and thermopower. This has historically excluded them from thermoelectric applications. However, progress in nanocomposites and other hybrid systems has made it reasonable to consider polymer-based systems as lightweight and economical thermoelectric material. The challenge in any effort to discover new TE materials lies in achieving simultaneously high electronic conductivity, high thermoelectric power and low thermal conductivity in the same solid. Our research program is developing new materials for fabricating high-performance thermoelectric devices. Students will engage in synthesis of new materials and also participate in constructing new device configurations for producing nanoscale thermoelectric devices.
Professor Gregory Grason Polymer Science & Engineering
G. Modeling Self-Limited Assemblies of Chiral Nanofilaments
(This student would jointly participate in the Soft Matter Research in Theory - SMaRT Program - an interdisciplinary REU position within the Department of Polymer Science & Engineering, introducing undergraduate students to the particular challenges, methods and opportunities of theoretical research in soft materials.)

Inspired by a wealth of experimental observations of finite-sized bundle or fibril formation in a range biological systems, this project will explore thermodynamic mechanisms for assembly of molecular filaments. The ubiquitous helical structure of intracellular filaments like actin or extracellular filaments like collagen, favors neighbor molecules to twist with a preferred handedness. A local tendency for filaments to twist is geometrically incompatible with the preferred global arrangement of filaments, a two-dimensional lattice in cross section. This project will explore how chiral interactions frustrate the lateral assembly of filaments, leading to thermodynamically limited bundle radii. Specifically it addresses the question, how do structure and interactions of individual molecules relate to the equilibrium sizes of observed filament bundles?
Professor M. Muthukumar Polymer Science & Engineering
H. Molecular Modeling of Polymer Translocation
(This student would jointly participate in the Soft Matter Research in Theory - SMaRT Program - an interdisciplinary REU position within the Department of Polymer Science & Engineering, introducing undergraduate students to the particular challenges, methods and opportunities of theoretical research in soft materials.)


This project focuses on movement of polynucleotides and proteins through protein channels.
Professor Vince Rotello Chemistry
I. Nanoparticle-based Sensing of Proteins, Bacteria, and Human Cells
Professor Vince Rotello Chemistry
J. Drug, DNA, and siRNA Delivery to Cells Using Gold Nanoparticles
Professor Vince Rotello Chemistry
K. Integrating Top-down Nanofabrication Processes with Bottom-up Nanoparticle Assembly
Professor Greg Tew Polymer Science & Engineering
L. Synthetic Cell Penetrating Peptide Mimics
Herein, we introduce synthetic guanidinium-rich polymers which compared to polyarginine are more hydrophobic and have a more shape-persistent scaffold, namely polyguanidino-oxanorbornene (PGON) transporters. We provide an extensive characterization of their membrane activity including the dependence on pH, concentration, length, membrane fluidity, membrane and surface potential. The global responsiveness of these transporters reveals significant differences when compared with similar systems. Their overall ability to respond to chemical stimulation by both activation and inactivation is similar to CPPs, although PGONs show different selectivities than CPPs. These findings imply that PGON-counterion complexes could act as multicomponent sensors in complex matrices, a promising application of membrane transporters that attracts current scientific attention but has so far been limited to synthetic multifunctional pores. Lactate sensing in milk, with lactate oxidase for signal generation and Cascade Blue (CB) hydrazide for signal amplification, is used to demonstrate their potential in this area. We thus believe that PGONs could serve as an easily accessible membrane transporter, which complements the toolbox of available optical signal transducers in analyte sensing across membranes.
Professor Greg Tew Polymer Science & Engineering
M. Novel Hydrogels with Tunable Properties
Hydrogels have gained interest in the area of biomaterials for their many attractive qualities including high water content, porous structure, and tunable gelation conditions. These qualities allow the integration of such materials in the body as tissue scaffolds by offering structural support and allowing influx of cell metabolites and efflux of cell waste through their pores. Of even greater interest is to design hydrogels that can incorporate cells in a three dimensional structure while eventually degrading to leave behind only healthy tissue. In general ABA amphiphilic block copolymers form associative networks in water where the A block is hydrophobic and the B block is hydrophilic. This self-assembly is driven by the association of the hydrophobic endblocks into micellar structures, which are bridged by the water-soluble midblocks and form physically crosslinked networks. These physical hydrogels are attractive because no crosslinking agent is necessary and the gelation can be triggered by physically relevant stimuli (body temperature and pH). However, a number of groups have chemically crosslinked these polymers as well. Chemical crosslinking leads to a more permanent three-dimensional structure than the physically crosslinked counter-parts, but can still be degraded with time, and can be modified to incorporate proteins or adhesion peptides to increase the adhesion of cells to the scaffold.