UMass Amherst

2010 SURE Projects

AdvisorDepartment
Professor Marc Acherman Physics
A. Optical Experiments with Nanomaterials
In this project you will learn to set up, conduct, and participate in optical experiments in order to study novel nanoscale materials. Specifically, we are interested in the optical properties of semiconductor, metal and organic nanostructures. Understanding these nanomaterials will promote their implementation in solid-state lighting, sensor, and light-harvesting applications (e.g. solar cells). In addition to standard, steady-state optical characterization, our experiments rely on various time-resolved optical spectroscopy techniques in combination with far- and near-field optical microscopies.
Professor Mike Barnes Chemistry
B. Single Molecule Spectroscopy of Optoelectronic Nanomaterials
This project will involve assisting in experiments probing hotophysical properties of individual hybrid nanostructures comprised of an inorganic semiconducting core and conjugated organic ligands coordinated to the core surface. The REU student will be involved in both experimental preparation, fluorescence lifetime imaging and data analysis.
Professor Ryan Hayward Polymer Science & Engineering
C. 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
D. 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
E. Title TBA
In a photovoltaic cell, light photons are absorbed by a chromophore and creating excited electron-hole pairs (excitons). Typical exciton diffusion distances are of the order of 5-20 nm. Therefore, in order to efficiently harvest electron, the separation distance between the conducting or semi-conducting elements that remove the electron 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
F. 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
G. Organic-Inorganic Hybrid Nanowires for Photovoltaic Applications
The goal of our proposed research is to enable the integration of organic and inorganic materials for investigating interfacial charge generation, exciton diffusion, and basic charge transport. We will combine 1-D inorganic nanowires (e.g. ZnO, CdSe) with organic and polymer semiconductors for producing high-performance hybrid materials. We will also combine 1-D and 2-D organic single crystals with inorganic semiconductors to produce hybrid materials with unique electronic and optical properties. Electrical experiments will be carried out for extracting the physical properties of these newly developed multifunctional materials by employing basic device architectures. Our research efforts will enable our program to bridge fundamental science with applied research.
Professor Al Crosby Polymer Science & Engineering
H. Nanoparticle Assemblies for Tailored Mechanical Properties
From the wrinkles on our skin to the snapping of the Venus Flytrap, instabilities are ubiquitous in Nature fore defining shape, structure, and function. We use elastic and fluid instabilities to create novel hierarchical structures in polymer nanocomposites. Taking advantage of true nanoscale effects of nanoparticles in polymer matrices, we design assemblies that will alter their nanostructure upon application of mechanical energy to extend the material's ductility.
Professor Gregory Grason Polymer Science & Engineering
I. 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
J. 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 Mike Maroney Chemistry
K. Biohybrid Materials for Hydrogen Generation and Utilization
The proposed project involves the design and synthesis of materials for the production and utilization of hydrogen, using an approach involving the replacement of the electron donor or the drain (acceptor) in the physiological systems with judiciously chosen semiconductors. The work involves isolation and purification of hydrogenase, and modification of surface residues for covalent attachment to semiconductor materials. If successful, the catalytic properties of the materials will be characterized.
Professor Vince Rotello Chemistry
L. Nanoparticle-based sensing of proteins, bacteria, and human cells
Professor Vince Rotello Chemistry
M. Drug, DNA, and siRNA delivery to cells using gold nanoparticles
Professor Vince Rotello Chemistry
N. Integrating top-down nanofabrication processes with bottom-up nanoparticle assembly
Professor Greg Tew Polymer Science & Engineering
O. 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
P. 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.
Professor S. Thayumanavan Chemistry
Q. Polymeric Nanostructures Towards Enhancing Solar Cell Performance
The fundamental challenge in materials for photovoltaics is to enhance the efficiency of charge-separated states and/or slow down charge recombination. Incorporating the elements of photovoltaics within organized nanoscale assemblies is a promising approach towards achieving this goal. In this direction, Thayumanavan group is involved in achieving morphologies that one could obtain using block copolymers or nanoporous templates containing photoactive and charge transport units in the appropriate domains. These efforts will provide fundamental insights into the structure-property relationships in terms of the roles of individual molecules vs. bulk morphology in the overall performance of the materials as components of solar cells.
Professor D. Venkataraman Chemistry
R. Photovoltaic Devices Based on Inorganic Semiconductors
In hybrid photovoltaic cells, semiconductor nanoscale structures are used as electron conductors. For efficient charge transport, the length of the nanoscale structures should be on the order of micrometers and the width of the rod should be in nanometers. Moreover, the semiconductor rods should be oriented perpendicular to the electrode surface for efficient charge collection. Our approach involves the use of electrochemical deposition within the pores of a nanoporous template and the removal of template after the deposition. Our work involves optimization of electrochemical conditions to obtain the targeted phase of the semiconductors in a crystalline form and fabricate photovoltaic devices.
Professor D. Venkataraman Chemistry
S. Photovoltaic Devices Based on Organic Semiconductors
For efficient organic or hybrid photovoltaic cells, hole-conducting and electron-conducting organic moieties need to be assembled into segregated structures. This allows the exciton to split at the interface. Yet, it is favorable for hole-conducting moieties mix with electron-conducting moieties. How do we keep them separated? Our approach involves appending groups to electron-rich and electron-poor moieties such that the interaction between these groups will be unfavorable. The underlying hypothesis of our approach is that mixing of electron-rich and electron-poor moieties will be disfavored because of the immisciblity between the groups appended on them.