Research Experiences for Undergraduates
The Triangle MRSEC focuses on studying programmed assembly of soft matter, inventing materials that have never before existed and creating new ways to use those materials. Join our collaborative and interdisciplinary center for an exciting Research Experience for Undergraduates (REU) program. Oustanding undergraduates will paraticipate in a nine-week summer program designed to provide unique research experiences, professional development opportunities, and increased awareness of materials science and engineering. Each student will participate in an innovative research project that probes fundamental aspects of experimental and/or theoretical soft matter science under the guidance of a faculty and a graduate student mentor. Each REU project is designed to involve the student in all aspects of research, from project planning and experimental design to data analysis and presentation. Triangle MRSEC REU students have access to state-of-the art facilities and resources at Duke and NCSU, participate in several professional development and networking activities, and conduct research in a highly collaborative and interdisciplinary environment.
When to Apply
We will begin accepting applications in January 2014.
Before you apply you will need to:
- Prepare your resume and unofficial transcript.
- Write a one page double spaced essay answering the question: Why are you interested in an REU in soft matter?
- Review the projects below, you will be asked to select your top three.
Follow this link to access the MRSEC REU Application Form.
After you apply you will need to:
- Have two recommendations sent to us (download instructions to give to your references)
- All materials must be recieved by March 3, 2014.
- If you have any questions, please contact us by e-mail: firstname.lastname@example.org
Recommendations should be:
- Emailed to: email@example.com OR
- Mailed to: Triangle MRSEC
Attn: Catherine Reyes
Durham, NC 27708
- 9 weeks housing on Duke's or North Carolina State University's campus
- $4200 stipend
- Up to $400 towards travel costs
Equal Opportunity Statement
Duke University and Duke University Health System are committed to affirmative action and fair employment. Whether in the classroom, the clinic, or elsewhere on or off campus, we believe in giving everyone the opportunity to succeed. Our commitment to principles of fairness and respect for all helps create a climate that is favorable to the free and open exchange of ideas and reinforces our knowledge that our differences are a source of strength, which help foster new opportunities in education, research, and patient care.
All applicants must be United States citizens or permanent residents and have health insurance coverage. Students entering their junior or senior year will be given preference, but exceptional entering sophomores will be considered.
- Students arrive: May 25-26
- Orientation: May 27
- Duke ends: July 26
- NC State ends: August 2
Research Opportunities for 2014
Soft Biomimetic Actuators
Professors: Michael Dickey, NCSU
Key background knowledge needed: Students with a chemical or mechanical engineering or chemistry backgrounds are preferred
Nature abounds with examples of soft actuators, including muscle, squid, octopi, and certain insects. The goal of this project is to construct and study soft actuators, which are materials that move in response to a stimulus (e.g., voltage, pressure, pH, chemicals, etc.) and have mechanical properties that are soft. The project, which can evolve in several ways depending on student interest, will benefit from someone who is enthusiastic and creative. We envision the soft actuators being created by combining elastomeric polymers with a moldable liquid metal. The metal will be used to create soft electrodes that can apply electric fields to enable new modes of deformation. The work will be highly collaborative within the Dickey research group at NCSU and with the group of Prof. Xuanhe Zhao at Duke. The Dickey group studies soft materials, thin films, and interfaces and is interested in patterning, microfabrication, and soft / stretchable electronics. The Zhao group studies soft active materials.
Computational and Theoretical Study of Colloidal Assembly
Professor: Patrick Charbonneau, Duke University
Key background knowledge needed: one year of physical chemistry (for chemists)/thermal physics (for physicists), or equivalent, and (ideally) some computer programming experience.
The relationship between material properties and their microstructure underlies a quest for ever greater structural control and diversity. This can be quite challenging, but “bottom up” colloidal self-assembly techniques are a promising way to achieve control and diversity. Colloidal building blocks are relatively cheap and are of the appropriate size (10nm – 10um) for building functionality in the infrared and visible wavelengths. Additionally, their interaction can be tailored to spontaneously assemble into a variety of structures. Yet identifying the relevant parameters for controlling the assembly remains challenging. The computational and theoretical tools necessary to address this problem for a family of systems are sufficiently sophisticated to guide the process. This project will allow an you to gain experience in computational and theoretical materials studies, including molecular dynamics and Monte Carlo methods, and to compare the research results with experimental work conducted within Triangle MRSEC.
Tailoring the density of grafted (syntactomer) peptides by mechanical deformation of underlying substrates
Professor: Jan Genzer, North Carolina State University
Key background knowledge needed: Basic chemistry lab skills
The purpose of this project is to develop a method for controlling the density of peptide molecules (i.e., syntactomers) on flexible silicone rubbers. The peptide molecules will be attached chemically to functional silicone networks featuring poly(vinylmethyl siloxane) (PVMS) that has been surface-modified with carboxylic acid-terminated thiol linkers (via thiol-ene click chemistry). Using standard peptide coupling protocols, the amine end-groups of the peptides will be reacted with the terminal –COOH groups on the surface. The density of peptides will be adjusted by mechanically pre-stretching the PVMS network substrate before peptide attachment. Releasing the strain applied to the network after peptide coupling will increase the peptide grafting density. These peptide assemblies are anticipated to adopt different configurations depending on the magnitude of the strain applied. The characteristics of the peptide-grafted surfaces will be studied by means of a battery of analytical methods available in the Genzer group. In addition, in collaboration with the Zauscher group at Duke University, we will examine the in-plane organization of the peptide arrays via scanning probe microscopy.
Professor: Stephen Craig, Duke University
The Craig group is developing “mechanophores” – molecules that sense and respond to an applied mechanical force – for use in new classes of stress-responsive polymers. Current work is focused on incorporating mechanophores into soft devices such as microfluidics and soft robots, with a goal of adding new “on/off” stress-responsive functionality (color change, catalysis, release of small molecules) to important technological platforms. This research provides undergraduate researchers with experience in organic and polymer synthesis that is coupled to materials testing in an iterative optimization process.
Professor: Chuan-Ha Chen, Duke University
The objective of this project is to create self-cleaning materials that function regardless of external forces, including gravity. The project takes advantage of the jumping-drop discovery at Duke, where water condensate self-propels to jump away from superhydrophobic surfaces, carrying away contaminants in the condensate drop. The background is discussed in this article in Scientific American. This project is primarily experimental but will also involve the development of scaling laws. The student will have the opportunity to use high-speed photography to capature the self-cleaning process at up to a million frames per second, and use mechanistic understanding to guide the engineering of practical self-cleaning materials.
Surface Energy Harvesting
Professor: Chuan-Ha Chen, Duke University
The objective of this project is to create an engineering device that harvests environmental energy, mimicking the ballistospore fungi which discharge spores by the so-called one-shot microengines powered by surface energy. This biological process has been reproduced at Duke: coalescing condensate droplets on a superhydrophobic surface release surface energy, which is eventually converted to kinetic energy propelling the droplets to jump. The background is discussed in this news article in Science. This project is primarily experimental but will also involve the development of scaling laws. The student will have the opportunity to use high-speed photography to capture surface energy conversion process of ballistospore discharge at one million frames-per-second, and use the mechanistic understanding to guide the design and development of an engineering prototype that mimics this energy harvesting process.
Bioinspired Mineralization of Self-Assembled Nanomaterials
Professor: Gabriel Lopez, Duke University
Self-assembled supramolecular structures have shown great promise as drug delivery vehicles and components of biosensing devices. These structures are successful because their amphiphilic constituents, such as polypeptides, spontaneously assemble though hydrophobic interactions into ordered structures that can easily incorporate desired functional components (e.g., targeting ligands). However, these assemblies are not covalently bound and thus unstable. Silica encapsulation has been shown to increase functional stability of a multitude of structures, including enzymes and whole cells. Our lab is developing precise methods of silica deposition onto self-assembled biomimetic materials with control over silica structure (e.g., porosity and thickness). We aim to stabilize these assemblies to maintain suitable transport kinetics necessary for optimal function. The goal of the REU student would be to learn and apply sol-gel processes in design and synthesis of hybrid nano-particles.
Preparation and Characterization of Polymer Composites Containing Magnetically Chained Nanoparticles
Professor: Joseph Tracy, North Carolina State University
Magnetic nanoparticles (NPs) dispersed in solvents can self-assemble into chains when magnetic fields are applied. If the solvent can be polymerized or contains a polymer, then the magnetic NP chains can be embedded into the polymer and preserved after removing the magnetic field. Our recent paper in Particle & Particle Systems Characterization
demonstrates this concept. The chains can impart anisotropic magnetic, optical, and mechanical properties to the polymer composite. The objectives of this project are to better understand the process of chaining magnetic NPs, to obtain improved control over the chain morphology, and to control the properties of these composites. The REU student will synthesize magnetic NPs, embed them into polymers, and use state-of-the-art characterization techniques to measure the properties of the NPs and of the composites.
Materials Characterization of Conducting Polymer Thin Films Deposited by Resonant-Infrared Matrix-Assisted Pulsed Laser Evaporation (RIR-MAPLE)
Professor: Adrienne D. Stiff-Roberts, Duke University
RIR-MAPLE is an organic-based thin-film deposition technique appropriate for polymeric optical coatings (such as anti-reflective coatings) and organic optoelectronic devices (such as solar cells). RIR-MAPLE has been shown to deposit polymeric thin films with very different morphologies compared to spin-cast films. In this project, the student will investigate the materials properties of conducting polymer thin films deposited by RIR-MAPLE using atomic force microscopy, UV-Visible absorption spectroscopy, photoluminescence spectroscopy, and photocurrent-voltage measurements in order to determine the film morphology and the resulting impact on vertical charge transport.
Light Induced DNA Self-Assembly
Professor: Stefan Zauscher, Duke University
The purpose of this project is to develop light-sensitive, single-stranded DNA (ssDNA) macromolecules by incorporating photo-responsive groups including spiropyran and azobenzene. These functional polynucleotides self-assemble into micellar nanosstructures which have potential for triggered drug-delivery applications. ssDNA polynucleotides are synthesized enzymatically via Terminal Deoxynucleotidyl Transferase (TdT) catalyzed DNA polymerization, and the photoresponsive groups are incorporated at the chain ends via copper-free click chemistry. This coupling chemistry provides high yields and produces no byproducts under mild conditions. The spiropyran and azobenzene groups are able to switch between hydrophobic and hydrophilic states via photoisomerization under UV or visible light. Since ssDNA is hydrophilic, the reversible switching from a hydrophilic to a hydrophobic state of the photo-responsive groups can trigger the self-assembly of the functionalized ssDNA into micelles. The REU student will work on the synthesis and characterization of these light-sensitive ssDNA polynucleotides, and learn to use gel electrophoresis, UV/Vis spectroscopy, atomic force microscopy (AFM) and dynamic light scattering (DLS).
Patterned Nanowire Networks
Professor: Stefan Zauscher, Duke University
Metal nanowire networks have shown a combination of high conductivity, flexibility and transparency, which leads to wide application in flexible electronics and photovoltaic devices. Typically, those nanowire networks are randomly formed, which results in a trade-off between conductivity and transparency. To increase the conductivity while maintaining high transparency, a patterned nanowire network is preferred. However, conventional patterning techniques often do not scale-up to meet the requirement of industrial application. Ferroelectric PZT thin films, which can maintain a highly localized, stable and switchable polarization state, could, however, be used to pattern nanowires on a large scale. By polarizing PZT films, the band structure of the PZT bends locally, and with UV illumination, electrons from the valence band can be excited to the conduction band and therefore reduce metal ions (here AuCl4+) from the solution into nanoparticle seeds (i.e., Au) on the surface of the film. Patterning can be accomplished in two ways, one by local charge polarization of the PZT, or by using laser interference patterns on bulk polarized PZT films. The patterned seeds can then be further grown into patterned nanowire networks. The REU student will prepare PZT films, pattern these films, and be learning how to use electron microscopy (SEM) and photoelectron spectroscopy (XPS), verify the formation of Au seeds on the PZT surface. In a subsequent reaction, the student will develop these seeds into a nanowire network.
DNA Networks on Surfaces
Professor: Stefan Zauscher, Duke University
The specific base-pairing recognition of DNA has been used for the programmable self-assembly of 2D DNA nanostructures. Yet despite the astounding successes in the field of DNA nanotechnology, the alignment, patterning and large scale ordering of polynucleotide strand assemblies on surfaces are still challenging problems that prevent use of these materials in functional devices. In this project, our aim is to generate a facile and reliable method that overcomes some of the current scaling-limitations of DNA nanofabrication by providing access to oriented DNA nanowire network structures over large areas, and thus contribute to an essential need in the ever growing number of nanoscale devices, ranging from flexible electronics to photovoltaic applications. We are able to fabricate 2D DNA networks on surfaces and over large areas, by harnessing our ability to enzymatically synthesize complementary DNA strands with control over strand length and chemical functionality. During this project, the student will first study the effect of concentration and length of the complementary DNA strands and then turn to explore ways to pattern and align the DNA networks over large areas. Finally the student will use the DNA networks as scaffolds for metallization, making nanowire networks. The REU student will be exposed to enzymatic polynucleotide synthesis and to surface characterization techniques, including atomic force microscopy (AFM) and electron microscopy.
Large Scale Synthesis of High Aspect Ratio Copper Nanowires for High-Performance Transparent Conducting Films
Professor: Benjamin Wiley, Duke University
The Wiley Lab focuses on the relationships of synthesis, structure and property of metal nanowires for transparent conducting films. Metal nanowires are currently the only alternative to ITO used in touch screens, OLEDs, and organic solar cells because they can be deposited from solution at speeds orders of magnitude faster than sputtering techniques for ITO deposition. Previous simulation and experiments have demonstrated that increasing nanowire aspect ratio has a profound effect on the properties of nanowire films. The Wiley Lab has recently developed a new synthesis to produce copper nanowire with aspect ratios as high as 5700 in 30 min (published in Chemical Communications). These nanowires were used to make transparent conducting films with a transmittance >95% at a sheet resistance <100 Ohm square-1, the highest performance to date for a solution-coated, copper nanowire-based transparent electrode. Thanks to their excellent conductivity and transparency, these high-aspect-ratio copper nanowires are expected to show better performance when they are incorporated into optoelectronic devices. Due to high demand in use by the laboratory and their collaborators, the Wiley Lab is motivated to improving the current synthesis in terms of yield and scale. This project will allow students to gain experience in toubleshooting nanowire syntheses, as well as the characterization of transparent, conducting nanowire films.
Assembly of magnetic colloidal crystals
Professor: Joshua Socolar, Duke University
We are interested in developing a flexible physical system that allows us to create crystalline arrays of colloidal particles that meet various design requirements. The Socolar group work does theoretical work in collaboration with the Charbonneau group and collaborates closely with the Yellen experimental group. The latter conducts experiments on the aggregation of magnetic colloidal particles in a magnetic fluid, a system that may support a variety of stable crystalline patterns. We are exploring ways of manipulating the applied magnetic field to induce the system to form patterns of our choosing. The work involves a combination of pencil-and-paper theory, numerical simulation, and numerical computation of energies of different structures. The ultimate goal is to create materials with specified (and perhaps unusual) elastic or optical properties.
Computer Simulations of Self-Assembly of Biopolymers
Professor: Yara Yingling, North Carolina State University
Simulations can assist and accelerate the design of hierarchal supramolecular architectures by elucidating structure and dynamics of individual polypeptides, binding energies, kinetics and thermodynamic and by guiding the experimental procedures. We are using atomistic and coarse-grained simulations to model our systems. Atomistic simulations, where all the atoms and interactions in the system are explicitly present, provide insights into the sequence dependent molecular structure and dynamics, relative importance of electrostatics and hydrogen bonding, effect of solvent and temperature. Coarse-grained simulations permit studies of the self-assembly process and formation of higher order assemblies. In this project, simulations will be used to predict and explain the effect of ionic strength, sequence and the chain length on assembly of micelles. Moreover, the temperature-dependent contributions to the stability of the polymer structures will be analyzed and used as a guide for polypeptide sequence engineering.
Temperature-Triggered Micellization of ELP-DNA Block Copolymers
Professors: Ashutosh Chilkoti, Duke University
Many efforts have been made to advance new drug delivery systems with optimal therapeutic activity while minimizing negative side effects. A system based on the reversible micellar self-assembly of amphiphilic block copolymers is becoming an increasingly interesting candidate as a drug delivery vehicle. Here we develop novel block copolymer systems that consist of a polypeptide block with a thermally reversible phase transition (Tt) and a hydrophilic, single stranded polydeoxynucleotide (ssPDN) block. The polypeptide block also serves as a macroinitiator for the enzymatic growth of the ssPDN block, using a template-independent polymerase –terminal deoxynucleotidyl transferase (TdT). The REU project will focus on the characterization of the resulting diblock copolymers and their self assembly behavior as a function of block molecular weight and temperature. Students will work in a team environment and will be trained in relevant characterization techniques such as static light scattering, AFM imaging, and small angle X-ray scattering.
Genetically-Encoded Stimulus Responsive Self-Assembled Polypeptide Nanostructures
Professor: Ashutosh Chilkoti, Duke University
Elastin-like polypeptides (ELPs) are artificial polypeptides with a pentapeptide repeat unit, Val-Pro-Gly-Xaa-Gly (VPGXG), originally found as an oligomeric sequence in native elastin, that display inverse phase transition behavior in aqueous solution. We have recently discovered a remarkably simple approach to drive the self-assembly of this class of peptide polymers into diverse nanoscale morphologies simply by appending a short (ZGG)8 segment to a (VPGXG)m segment and tuning the hydrophobicity of this Z residue to control self-assembly. We have found that polymers with Z = Trp (W) and Phe (F) form vesicles, while Z = Tyr (Y) forms near monodisperse worm-like micelles. Because the ELP segment imparts stimulus-responsive LCST phase behavior to the nanostructures in response to diverse triggers beyond temperature (e.g., pH, metal ion binding, ligand binding, and light), a wealth of opportunity awaits in creating “smart” –stimulus responsive– self-assembled structures with this class of peptide polymers. Moving forward, the questions that we wish to answer are:
(1) What are the rules at the sequence and composition level that control the self-assembly and the morphology of the ensuing structures?
(2) What are the structural properties of these self-assemblies, such as their stability, their mechanical properties (relevant to vesicles), their permeability to different solutes (relevant to vesicles), and their ability to sequester solutes in their core (relevant to micelles)?
(3) What impact does the stimulus responsiveness of these self-assembled structures have on their morphology, stability and structural properties?
(4) How can we exploit their triggered assembly-disassembly to program higher dynamic hierarchical structures such as: (i) micelles within vesicles and multi-compartment vesicles wherein the assembly and disassembly of each compartment can be independently controlled; (ii) dynamic bulk materials composed of stimulus responsive nano-mesoscale building blocks?
Deposition of Thin Nanocoatings from Janus Particles for Photonic and Energy Applications
Professor: Orlin D. Velev, North Carolina State University
The deposition of thin nanoparticle coatings can improve the performance of solar cells, “smart” windows, heat-dissipating films and other functional nanomaterials. This REU project will use a technique for simple and efficient convective assembly of nanocoatings for the deposition of a new class of special Janus particles. These particles will have one metallic and one polymer side and thus will possess interesting optical and conductance properties. By depositing them in nanocoatings we will use the unusual properties of the Janus particles in new types of materials and devices that can change color, reflectance, heat and electrical conductance on demand. Key background knowledge needed: This is an experimental project, which will require some laboratory expertise, good communication skills and ability to work with a diverse group of graduate students and postdoctoral fellows.