Marya Lieberman

Surface and Materials Chemistry

Department of Chemistry and Biochemistry
University of Notre Dame
Notre Dame, IN 46556
(219) 631-4665
(219) 631-6652 fax
mlieberm@nd.edu

Research in the Lieberman group focuses on the use of molecules as structural and electronic elements in materials and nanometer-scale electronic devices. The group spans inorganic, organic, biochemistry, and physical chemistry. Prof. Lieberman is the director of the Nano-Bioengineering REU program and her teaching interests include general chemistry, organic and inorganic chemistry, modern spectroscopy, surface and materials chemistry, science literacy, and science policy.

Quantum-dot cellular automata

Phthalocyanine SAMs

Reactivity in SAMs

Molecular Liftoff

Implants

  

Group members

Info for visitors

Recent publications

Virtual lab tour

    

Molecular analogs of quantum-dot cellular automata (QCA cells)

Find out more about QCA by visiting the QCA home page--this contains links that will lead you to basic theory, a nice Java simulation of cell operation, paper reprints, and all the home pages of the project participants.

This collaborative project involves faculty from both the Chemistry department and the Electrical Engineering department. Funded by the National Science Foundation, we study molecular implementations of quantum-dot cellular automata.

Quantum-dot cellular automata (QCA) are a completely new architecture for computation. Information is transmitted between QCA cells through Coulomb interactions; depending on the arrangement of the cells, bits can be transmitted, inverted, or processed with logic operations (AND, OR). Information processing does not require the flow of current, so QCA has the potential for extremely low power operation.

QCA cells consist of four quantum dots (structures which can contain charge) arranged in a square, with two extra electrons or holes that tunnel from dot to dot during operation. Switching the cell depends not on voltage gating of a current (as transistors do) but on this tunneling process; thus, the device performance is expected to improve the smaller the QCA cells can be made, with the ultimate size limit being molecular QCA cells.

Our group's part in this collaborative project is to synthesize and attach to surfaces a family of molecular QCA cells. Classical inorganic coordination chemistry is our main tool for the synthetic work; most of the molecules we are working with are made using standard Schlenk-line techniques. Both ultra-high vacuum scanning tunneling microscopy and X-ray photoelectron spectroscopy are employed to characterize model compounds and molecular QCA cells.

The synthetic effort is spearheaded by Wei He with participation from undergraduate researchers Sean Walsh and postdoc Roger Nassar. Michelle Viglietta, now a grad student at Duke, got the project going. We also study the binding of QCA cells and model compounds to surfaces using the XPS system and our new vacuum STM.

Self-assembled monolayers and multilayers of phthalocyanines

Phthalocyanines can act as structural building blocks in monolayer and multilayer films. Phthalocyanines are macrocycles related to hemes; they have enormous optical absorbances which are strongly polarized in the plane of the macrocycle. This means that oriented films of phthalocyanines could have some very interesting optical properties. Phthalocyanines are also useful components in organic photovoltaic cells, an application of some interest to us. This project was initiated by Zhiyong Li (Ph. D. May 2001) and is being continued by Wei He, who is making side-by-side Pc dimers and investigating their surface binding properties. We also have an ongoing collaboration with Prof. Dave Alonso at Andrews University, and several of his undergraduate students have participated in this reseach.

This "octopus" phthalocyanine with eight thiol "arms" binds to gold surfaces to form a self-assembled monolayer, or SAM.

We have explored a number of strategies to control the orientation of the phthalocyanine ring on gold surfaces. We can place thiol groups, which bind strongly to gold, at different locations in the molecule. X-ray photoelectron spectroscopy is then used to probe the structure of the monolayer films which assemble on flat gold surfaces. In particular, if the molecule being tested has multiple thiols, we can see how many of them bind on average. This work has begun to give us some insight into the general problem of designing surface anchors for large molecules.

Reactivity in SAMs

When the local environment of a molecule is constrained, it may react very differently than it does in solution. For example, anthracene undergoes a photodimerization in solution, but we are able to completely shut down its photoreactivity by binding it inside a self-assembled monolayer of a layered material.

Postdoctoral researcher Dr. Koshala Sarveswaran is studying the effect of SAM environments on various bond formation and cleavage reactions. The ultimate goal of this work is to design ultra-thin SAM resists that can be patterned using electron-beam lithography or electrochemical imprint lithography.

Molecular Liftoff

Graduate student Bo Gao uses ultra-high resolution lithographic techniques in coordination with chemical self-assembly to pattern a variety of molecules, nanoparticles, and biomolecules. She uses electron beam lithography (available right on campus at the Electrical Engineering Integrated Circuit Fabrication facility (the "fab")) to form sub-25 nm patterns which can then organize biomolecules at the surface. She uses AFM and biochemical techniques to understand how surface binding alters the structure of the biomolecules. Ultimately, we hope to direct the binding of individual biomolecules and nanoparticles using the liftoff technique.

Surface chemistry of artificial joint implants

Orthopedic surgeons implant artificial hip and knee implants in tens of thousands of people each year, yet the technology of bonding the implant to human bone limits the useful lifetime of the implants to 10-15 years. When failures in the implant/bone bond do occur, they usually happen right at the junction between the metal implant and the bone cement that is used to glue the implant into the bone. Therefore, it is critical to understand how the bone cement adheres to the metal surface. Amy Vickers and Dave Miller (an undergraduate participating in our summer REU program) studied implant adhesion from a surface chemistry perspective:

* surface composition is almost always quite different from bulk composition (think of the aluminum oxide film that forms on metallic aluminum). What is the surface composition of the implant, and how does this affect adhesion?

* can we increase the strength of adhesion to bone cement by altering the surface chemistry or by providing a covalent linker between the metal and the cement?

Chemistry and Public Policy

Scientists and policy-makers seem to inhabit two different worlds. Policy makers don't understand science or scientists, and scientists in turn are frustrated with the decision-making process employed by politicians and lawyers.

I am developing educational materials to bridge this gap. The project was funded by a special grant from the Camille and Henry Dreyfus Foundation; you can get a sense of the work in progress by visiting the web site for Chem 191 (Chemistry and Public Policy).

Quantum-dot cellular automata

Phthalocyanine SAMs

Reactivity in SAMs

Molecular Liftoff

Implants

  

Group members

Info for visitors

Recent publications

Virtual lab tour

    

Meet the Group

Graduate Students:

Postdoctoral research fellows:

Undergraduate Research Students

High School Teachers and Students

Graduate Students Who Have Actually Graduated (yes, it could happen to you!)

Postdoctoral students

Undergraduate students

Recent publications

  1. "Molecular Quantum-dot Cellular Automata,"C. S. Lent, B. Isaksen, and M. Lieberman, J. Am. Chem. Soc., 2003, 125, 1056-1063
  2. "Growth of Ultra-smooth Octadecytrichlorosilane Self-assembled Monolayers on SiO2," Y. Wang and M. Lieberman, Langmuir, 2003, 19, 1159-1167
  3. "Quantum-dot Cellular Automata at a Molecular Scale," M. Lieberman, S. Chellamma, B. Varughese, Y. Wang, C. S. Lent, G. H. Bernstein, G. L. Snider, and F. C. Peiris, Molecular Electronics II, Annals of the New York Academy of Sciences, 2002, 960, 225-239, Ari Aviram, Mark Ratner, and Vladimiro Mujica, Eds.
  4. "Molecular patterning through high-resolution polymethylmethacrylate masks," Q. Hang, Y. Wang, M. Lieberman, and G. Bernstein; A.P.L., 2002 80, 4220-4222.
  5. "XPS and SERS Study of Silicon Phthalocyanine Monolayers: Umbrella vs. Octopus Design Strategies for Formation of Oriented Monolayers," Z. Li, M. Lieberman, and W. Hill, Langmuir 2001, 17, 4887-4894.
  6. "Axial Reactivity of Soluble Silicon(IV) Phthalocyanines," Z. Li and M. Lieberman, Inorg. Chem. 2001, 40, 932-939.
  7. "Synthesis and Properties of [Ru2(acac)4(bptz)]n+ (n=0, 1) and Crystal Structure of [Ru2(acac)4(bptz)]," S. Chellamma and M. Lieberman, Inorg. Chem. 2001, 40, 3177-3180

Course Information

Surfaces and Interfaces

Chem 191(Chemistry and Public Policy)

Virtual lab tour

Our labs are situated in Stepan Hall at the University of Notre Dame. For a photographic tour of the lab and a peek at some of the denizens thereof, click on the map below. Other areas you may wish to tour are the nanofabrication labs, the vacuum STM, the XPS facility, the mechanical testing facility, our new vacuum AFM, and the Art Gallery. (pictures and links are being added...)


Information for Visitors

Getting to Notre Dame

By air:

Notre Dame is about 15 minutes from South Bend Regional Airport (Ask your travel agent or use an internet service such as Travelocity to book your tickets to South Bend, Indiana, SBN for short). You can get a cab or rental car at the airport.

You can also fly to Chicago O'Hare or Midway airport and take United Limo to the South Bend airport (~$31 one way). It will add about four hours of travel time.

By car:

From the north: The university is located just south of the Indiana Toll road (Interstate 80/90). Exit Interstate 80/90 at exit 77 and turn right onto Michigan Ave (Indiana 933). Make a left at the 4th stop light (Angela Boulevard). Make another left at the first stop light (Notre Dame Avenue). Look for a gate kiosk about halfway down the drive on your left; the guard at the gate can direct you to the visitor's parking lot.

From the south: Take US 31 north which becomes Indiana 933 just south of South Bend. Stay on Indiana 933 to Angela Boulevard which is the second stop light north of the St. Joseph River. Turn right onto Angela Boulevard then left at the first stop light onto Notre Dame Avenue. Look for a gate kiosk about halfway down the drive on your left.

More info for the traveller: links on the local weather, hotels, links to ND tourism....

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