SURE 2002 PROJECTS

The following research project descriptions are intended to give applicants to the CPIMA SURE program a feeling for the research opportunities within the three CPIMA partners - Stanford University, IBM Almaden Research Center, and University of California at Davis - as well as international and industrial affiliates.

The projects are grouped according to the corresponding research site. Each mentor's name is listed before the title of the project. If you wish to find out more information about a particular mentor, click on the name of the mentor.

Stanford University (top)

1) Design and Synthesis of Components in Supported Bilayer Membranes.
2) Adhesion and Debonding of Polymer Interfaces.
3) Grafting of Polypeptides on Solid Substrates.
4) Polymer Hydrogels for Lab-on-a-Chip Applications.
5) 2D Crystals Subject to Flow.
6) Electrical and Optical Devices Based on Semiconducting Polymers.
7) The Dynamics of Single DNA Chains Under Shear in Two and Three Dimensions.
8) Development of New Nitroxides for Controlled Free Radical Polymerization.

University of California - Davis (top)

9) Submicrometer Resolution in Optical Imaging Spectroscopy.
10) Biomimetic Systems for Probing Protein - Biomembrane Interactions.
11) Synthesis of Lipid End-Functionalized Polysaccharides for Anchoring Mobile Bilayers.
12) Nanoparticle Growth in Ultrathin Polymeric Film.
13) Fabrication of Supported Biomembranes and the Study of Their Functions.

IBM Almaden Research Center (top)

14) Contact Nanopatterning: Feature Transfer, Replication and New Uses.
15) Measurements of Polymer Segmental Mobility.
16) Synthesis and Properties of Nanoscopic Objects.
17) Organic Catalysis: A New and Broadly Useful Strategy for Living Polymerization.
18) Novel Macromolecular Architectures Based on Biocompatible Aliphatic Polyesters.
19) Controlled Polymerization Incorporating Latent Thermal Crosslinking Substituents.
20) Dynamics of Thin Film Polymers on Surfaces.

 

Affymetrix Co., Santa Clara, CA (top)

21) Photosensitive Polymers for Photolithographic Synthesis.

 

Max Planck Institute for Polymer Research, Mainz, Germany (top)

22) Supramolecular Science at the Max Planck Institute for Polymer Research I.
23) Supramolecular Science at the Max Planck Institute for Polymer Research II.

1) (S. Boxer) Design and Synthesis of Components in Supported Bilayer Membranes. (top)

The objective of this work is to create a new class of molecular systems that can be used to alter the self-assembly of supported bilayer membranes. Supported bilayers are two-dimensional fluids that can be contained within barriers or corrals that are patterned on surfaces. To date, such barriers have had static properties. In this project we will prepare barrier materials that can be switched with light or by a redox reaction such that the membrane fluidity properties are altered. This work will involve chemical synthesis, self-assembly on gold or on glass, surface characterization, and ultimately the further self assembly and characterization of supported lipid bilayer membranes over such switchable surfaces.

Adhesion and reliability of interfaces are crucial for a range of advanced technologies including applications in the microelectronic and biomedical industries. This project will involve developing techniques to measure the macroscopic adhesion valuesof a range of polymer interfaces that involve thin polymer layers or films. Adhesion values will be related to the underlying structure of the interface, its chemistry, and the properties of the adjacent materials.

Polypeptides are macromolecules composed of one or more types of amino acids. Whereas naturally occurring polypeptides or proteins have important biological properties, this project takes a biomaterials point of view. We will explore a variety of ways of attaching polypeptides to solid substrates to prepare templates for controlled adsorption of polymers or proteins. This has potential applications in the development of biocompatible surfaces and in membrane separations. The project will involve chemical synthesis and characterization of interfacial properties.

4) (C.W. Frank) Polymer Hydrogels for Lab-on-a-Chip Applications. (top)

Many academic and industrial research groups are currently developing techniques for miniaturization of laboratory wet chemical procedures. Such "lab-on-a-chip" devices combine mixing, pumping, reaction, and separation procedures on a single substrate. This project will focus on the development of surface-attached polymer hydrogels, which may have applications in valve and pump designs. Chemical synthesis of hydrogel networks and characterization of swelling and deswelling behavior will be carried out.

5) (G. Fuller) 2D Crystals Subject to Flow. (top)

Many systems form 2D crystals at fluid interfaces. Examples include colloidal particles and proteins. In this project the action of flow fields on 2D crystals formed from micron-sized spheres will be examined. The influence of altering the interparticle potential through changes in the ionic strength of the bulk fluid phases on the process of shear-induced melting will be examined.

6) (M. McGehee) Electrical and Optical Devices Based on Semiconducting Polymers. (top)

Semiconducting polymers will be used to make light-emitting diodes (LEDs) and photovoltaic cells from semiconducting polymers. The work with LEDs will involve tranferring energy from polymers to rare earth complexes to obtain narrow bandwidth emission spectra. The work with photovoltaic cells will involve self-assembling nanoporous titania films using block copolymer structure directing agents. The nanopores will be filled with semiconducting polymers. It is hoped that the polymer will carry photogenerated holes and that the titania will carry photogenerated electrons in such a way that the photoconductivity will be enhanced.

7) (E. Shaqfeh) The Dynamics of Single DNA Chains Under Shear in Two and Three Dimensions. (top)

The project will involve experiments examining the dynamics of single DNA chains either free in a liquid or near a solid-liquid interface under flow using strong video microscopy. In particular we shall examine, how the dynamics of the chains are affected by flow type and interfacial interaction. These experiments will be compared to computer simulations of DNA dynamics using models that we have developed over the last five years.
Prerequisite: Chemical engineering or physics major preferred.

8) (R. Waymouth) Development of New Nitroxides for Controlled Free Radical Polymerization. (top)

The controlled free-radical polymerization has provided a powerful strategy for the synthesis of macromolecules of well-defined architecture. This project will involve the synthesis of new alkoxyamine compounds for investigations in controlled living free-radical polymerization. Current challenges are to develop new alkoxyamines that can initiate polymerization in a controlled fashion at low temperatures as well as those that can be tolerated by olefin polymerization catalysts and incorporated into polyolefins. The incorporation of alkoxyamine structures into polyolefins is useful not only as free-radical initiators, but also as a novel class of flame-retardants for polyolefin plastics.
Prerequisite: Some synthetic experience in chemistry preferred.

Orientation of molecules at interfaces has gained much attention for a variety of problems ranging from surface contact problems such as friction and adhesion, to alignment of molecules on surfaces such as anchoring of liquid crystals at interfaces. To non-destructively identify the molecules at an interface, as well as determine their orientation and location, we are developing new optical techniques that are based on nonlinear optical effects present at interfaces. The challenge resides in developing instrumentation to position the sample, steer optical beams in the visible and infrared, and detect photons with great sensitivity. The research will involve the design and testing of new experimental concepts and the experimental investigation of spectra and orientation of molecules at interfaces.

10) (M. Longo) Biomimetic Systems for Probing Protein - Biomembrane Interactions. (top)

Lipids are amphiphilic molecules that form a bilayer structure that is the "matrix" of cell membranes and constitutes a two-dimensional fluid that is ultra-thin (3-4 nm). Many proteins are membrane associated and a diverse range of functions take place at membrane surfaces (e.g. energy production, ion transport, receptor-ligand interactions, and viral entry). This project will involve two related membrane problems. Firstly, there is a need to be able to predict and better understand where proteins and peptides (small protein) reside with respect to the membrane. The ultimate goal is to construct a rounded approach, involving experiments in which peptide sequences and membrane properties can be varied, and development of instructive theoretical algorithms. Thus, we have focused on methods and systems for detecting and learning about peptide/protein-membrane interaction and developing predictive models that capture the most important features of the peptide-bilayer system. Secondly, we have been involved in the development of enabling technology in the area of supported lipid bilayers. Our main motivation is in exploiting the great potential for using these systems to learn more about the interaction of peptides and other biopolymers with lipid bilayers.

Depositing bilayers onto surfaces with control over the distance between the bilayer and substrate surface is important for maintaining the mobility of the lipids and for sustaining the activity of transmembrane proteins anchored within the layer. Additionally, one would like to develop supports that mimic the cytoskeleton of cell membranes. This project involves synthetic organic and polymer chemistry targeted at preparing lipid end-functionalized dextrans of varying molar masses. These polymers will then be investigated as anchoring supports. The work will involve the synthesis of carbohydrate derivatives and their polymerization using cationic intermediates and lipid-derived initiators. A strong chemistry background is preferred for this work.
Prerequisite: Must have completed one year of organic chemistry laboratory.

12) (P. Stroeve) Nanoparticle Growth in Ultrathin Polymeric Film. (top)

In recent years, the fabrication of nanostructured materials and exploration of their properties have attracted the attention of the physicist, chemist, biologist and technologists alike. Interest in such systems arise from the fact that the mechanical, chemical, biological, electrical, optical, magnetic, electro-optical and magneto-optical properties of these particles are different from their bulk properties and depend on the particle size. In this work, we will study the nucleation and growth of nanoparticles in polymer films produced by the layer by layer deposition technique. The non-linear optical (NLO) properties of nanoparticles show large differences in their optical limiting behavior below and above the absorption edge suggesting that such systems may be utilized in high speed switching. While a major thrust in this area of research remains focussed on perfecting synthetic techniques to obtain nanoparticles with a narrow particle size distribution, it is worthwhile to investigate in some detail the changes in the optical properties brought about by aggregation of the nanoparticles and correlate them to the size and shape of the particles.
Prerequisite: Must be majoring in chemistry, biology, or chemical engineering.

13) (P. Stroeve) Fabrication of Supported Biomembranes and the Study of Their Functions. (top)

Phospholipid bilayers supported on flat solid substrates are both of practical and scientific interests as model systems to study the structure and function of natural membranes, as well as those of membrane-bound biomolecules. Hydrated polymer layers have been used as "cushions" to lift biomembranes from solid surfaces. The hydrated space created by the addition of a polymer layer is not only advantageous for decreasing the substrate effect on the membrane itself, but is also desirable for maintaining the activities of incorporated biomolecules. To explore the mobility of solid supported biomembranes cushioned by a hydrated polymer, we will focus on a model membrane system of lipid mixtures including an anionic phospholipid, a zwitterionic phospholipid and cholesterol. Surface plasmon resonance (SPR) will be used in this work to detect the adsorption of the polymer layer and the lipid layers. We also will use fluorescence recovery after photobleaching (FRAP) to measure the lateral mobility of the lipid membranes formed on the polymer layer. Supported biomembranes that retain fluidity may be useful as model systems for sensing molecules that interact with cell membranes. As a means to investigate sensing abilities and biological function, we will introduce proteins into our membrane system.
Prerequisite: Must be majoring in chemistry, biology, or chemical engineering.

The replication of increasingly smaller features via photolithography has been the driving force behind advances in microelectronics. The controlled creation of small features has also become increasingly important in other technology areas (biotechnology, data storage, displays, etc.). We are currently examining alternatives to photolithography via contact methods for the massive reproduction of sub-micron features (i.e. contact molding and embossing). A key challenge in contact nanopatterning is the design of suitable pattern molds from polymeric materials. This project will involve the design, synthesis, and characterization of new materials and surface functionalization of these patterned surfaces with technologically interesting materials.
Prerequisite: Must be a biochemistry, chemistry, chemical engineering or materials science major.

15) (J. Frommer) Measurements of Polymer Segmental Mobility. (top)

As organic thin films scale down to ultrathin dimensions, how do their material properties scale from the bulk? We are studying the mobility of polymer chains as they are confined within submicron feature sizes. Among the issues raised is the effect of polymer segmental motion on the diffusion of smaller, discrete molecules within the polymer matrix. The methods we use include lithographic techniques to create small domains, atomic force microscopy to probe localized features and properties, and custom synthesis to intentionally alter film properties.
Prerequisite: Must be comfortable handling chemicals and instrumentation.

A major new area of interest for chemists is the controlled fabrication of nanoscale objects, ca. 1-100 nm. We have recently developed a number of new synthetic procedures for the synthesis of well-defined macromolecules, dendrimer and living free radical polymerizations, which are perfectly suited to the preparation of objects and materials with these dimensions. Building on these advances and recently developed characterization techniques at IBM Almaden we propose to construct hollow, nanoscopic polymer spheres for wide range of applications such as drug-delivery systems, magnetic storage, and microelectronics.
Prerequisite: Chemistry major preferred.

17) (J. Hedrick) Organic Catalysis: A New and Broadly Useful Strategy for Living Polymerization. (top)

Advances in organometallic chemistry in the design and synthesis of single-site metal catalysts for olefin, ring-opening metathesis, and ring-opening polymerization techniques have enabled the preparation of well-defined functional polymeric materials with predictable molecular weights and narrow polydispersities. Surprisingly, relatively few polymerization reactions have been reported which employ simple organic molecules as reaction catalyst, despite the widespread availability of organic chemicals in enantiopure form. The ring-opening polymerization (ROP) of lactides, lactones and epoxides using nucleophilic organic catalysts such as amines, thiophenes, phosphines and imidizolidine carbenes has been investigated. The strategy employed for the ROP using organic catalysts is as follows. First, a nucleophile such as an alcohol must be used to initiate the polymerization of the cyclic monomer in the presence of the catalyst, which provides a means of molecular weight and end-group functionality control. Secondly, the ROP does not evolve a co-product and since the equilibrium is enthalpically driven, the equilibrium is prejudiced towards polymerization. Mild and highly selective polymerization conditions either in bulk or solution produced polymers with predictable molecular weights and extremely narrow polydispersities. New strategies for chiral and "planar-chiral" organocatalysts that enable the formation of highly enantioselective poly(lactides) and polyethers from racemic monomer mixtures will also be developed.
Prerequisite: Must be a chemistry major.

18) (J. Hedrick) Novel Macromolecular Architectures Based on Biocompatible Aliphatic Polyesters. (top)

Macromolecular engineering has assumed increasing importance in polymer science. One approach to complex molecular architectures is through the preparation of block copolymers or two distinctive homopolymers covalently bound at one point. Another approach to complex molecular architectures is the introduction of controlled branching. The use of ring-opening polymerization (ROP) methods to develop such new architectures has been much less pervasive than other synthetic techniques. Our interest is in the ROP of lactones, lactides, etc. and other related monomers. This project will involve the synthesis of new biocompatible polymers with the object of tailoring elastomeric mechanical properties with new molecular architectures.
Prerequisite: Must be a chemistry major.

Polymer crosslinking raises the glass transition temperature and often improves the mechanical properties of polymer films. We have developed latent thermal crosslinking functionality, which are compatible with a wide range of controlled polymerization procedures (e.g. living free radical, atom transfer radical, ring opening, and anionic polymerization). Thermal crosslinking after polymerization produces single molecule nanoparticles in dilute solution and intermolecular networks in films. These materials are useful in a range of technological applications including ultralow-k dielectric insulators, new materials for high-density storage, tethered nanostructures, surface modification etc. The project is primarily synthetic and involves the synthesis and characterization of new monomers and polymers for potential technological applications.
Prerequisite: Must be a chemistry or chemical engineering major.


20) (C. Wade) Dynamics of Thin Film Polymers on Surfaces. (top)

This project involves the use of spectroscopic and other surface science techniques to study dynamics (configuration, torsional motion, diffusion) of polymer molecules on surfaces, especially in sub-monolayer coverage. NMR (solid state and liquid), contact angle measurements, and scanning probe microscopies will be used to investigate the dynamics of functionalized perfluoropolyethers as a function of surface coverage and temperature on amorphous films. This project will be a collaborative interaction with several other CPIMA summer projects at IBM, so a precise definition of techniques to be used will depend on research status in June 2002. The student will prepare samples, measure surface concentrations, characterize the samples, and work with scientists to perform the measurements.
Prerequisite: Three years of chemistry is preferred.

Light directed combinatorial synthesis has enabled large-scale synthesis of DNA probe arrays containing hundreds of thousands of sequences by using repeated cycles of illumination and reagent coupling. This project will explore the use of photoresist-based systems as compared to traditional photochemical systems for the synthesis of DNA probe arrays. Photosensitive polymeric formulations that undergo a chemical or physical change upon exposure to light will be prepared and coated onto surfaces. Examples of common photosensitive reagents are photoacid generators and contrast enhancing materials. Photoresist based systems that exhibit a nonlinear response to irradiation will provide higher contrast and resolution and have the potential to facilitate printing very small sized features.
Prerequisite: Chemistry, physics, or chemical engineering major is beneficial.

We can offer a position for a summer student during 2002 for a project connected to the following research program: 1) Build-up of organic supramolecular architectures at interfaces, in particular, biomimetic systems comprising planar solid-supported lipid bilayers on the basis of glycolipids and the incorporation of transmembrane proteins. 2) Study of the formation and structure of these systems by various surface analytical methods such as surface plasmon resonance spectroscopy, impedance spectroscopy, epifluorescence microscopy, fluorescence recovery after photo bleaching (FRAP), atomic force microscopy (AFM), etc. 3) Investigation of the function and activity (in particular ion transport) of the incorporated proteins in particular of the Na/K-ATPase by impedance spectroscopy and other electrochemical techniques.
Prerequisite: Must have an interest in the physics and physicochemistry of biomimetic systems as well as some application aspects of our work (sensors, drug screening).

23) (W. Knoll) Hybrid Organo-metallic Channel Waveguides for Integrated Optical Biosensors. (top)

By a chemical vapor deposition technique, using organometallic precursor molecules, we are able to fabricate ultra thin layers of gold or palladium as deposits on top of self-assembled monolayers laterally patterned by micro-contact printing of end-functionalized thiol molecules. These metallic layers on top of a planar waveguide structure results in an enhancement of the guided optical field by modifying the effective refractive index in the region of the deposit. Within this project, we want to use this concept for the fabrication and characterization of channel waveguides as elements of an integrated optical bio-sensor platform. To this end, the hybrid organo-metallic channel waveguide structures will be further functionalized by thiol molecules that carry a biorecognition site (ligands, oligo saccharides, oligo nucleotides, etc.).
Prerequisite: Must have an interest in integrated optics, materials and surface science, and biosensor development.