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					        Nanoscience and Engineering Center (NSEC) for Directed Assembly of Nanostructures
                  Richard Siegel, Rensselaer Polytechnic Institute, DMR 0642573



              One of our NSEC’s senior faculty participants, Dr. Charles F. Zukoski,
              was elected to the National Academy of Engineering. He was cited “for
              research on the manipulation of particle interactions to alter their
              suspension properties, and for leadership in education.”



His research concentrates on understanding the
relationships between surface physical chemistry and
the material properties of colloidal suspensions.
Particular attention is paid to methods of manipulating
interparticle forces to alter particle and suspension
properties. Zukoski is the William H. and Janet G.
Lycan Professor in the Department of Chemical and
Biomolecular Engineering and Vice Chancellor for
Research at the University of Illinois at Urbana-                     Figure 1. Anisotropic particle suspensions.

Champaign.

                                                           Photo Credits: http://www.scs.uiuc.edu/~cfzgroup/index.php
               Nanoscience and Engineering Center (NSEC) for Directed Assembly of Nanostructures
                         Richard Siegel, Rensselaer Polytechnic Institute, DMR 0642573




                         Figure 2. Chain transfer reactions for the radicals (a) in solution and (b) on particle surfaces.


NSEC investigators Dr. Chang Y. Ryu and Brian C. Benicewicz authored one of the ten most-accessed articles in the journal
Macromolecules (April-June, 2006). The article’s popularity mirrors the scientific impact of this work. Macromolecules is
the most-cited journal in the area of Polymer Science, with 71,840 citations in 2005 - over 41,000 more citations than the
nearest ranked journal. It is also ranked third in impact factor out of the 75 journals in the polymer science category. The
article, “A Versatile Method To Prepare RAFT Agent Anchored Substrates and the Preparation of PMMA Grafted
Nanoparticles” was co-authored by Li, Han, Ryu, and Benicewicz. Researchers discovered a novel strategy to efficiently
graft polymers on nanoparticle surfaces using a controlled radical polymerization technique. This strategy is applicable for a
wide range of monomers to tailor the surface functionality of nanofillers including nanoparticles.
C. Li (RPI), J. Han (RPI), C.Y. Ryu (RPI), and B.C. Benicewicz (RPI), “A Versatile Method to Prepare RAFT Agent Anchored Substrates and the Preparation of
PMMA Grafted Nanoparticles”, Macromolecules 2006, 39, 3175 - 3183.
                   Nanoscience and Engineering Center (NSEC) for Directed Assembly of Nanostructures
                              Richard Siegel, Rensselaer Polytechnic Institute, DMR 0642573
    Rensselaer NSEC 0117792 - Room Temperature Assembly of Germanium Nanoparticle-based Photonic Crystals




Figure 3. Germanium nanoparticles (A) were infilled into the interstitial space of a colloidal crystal (B) formed from 1 micrometer
diameter polymer microspheres. The germanium nanoparticles were linked together using a photocurable epoxy, and the polymer
microspheres were dissolved, forming a germanium-based photonic crystal (C).



Through a rapid and low-cost directed self-assembly process, a nanoparticle-based photonic crystal, a three-
dimensionally periodic material with unique and powerful optical properties, was formed (Braun, Siegel).
Our photonic crystals exhibited the greatest photonic strength to date of any nanoparticle- based systems,
and in addition, we demonstrated, for the first time, that germanium nanoparticles could be directly used to
create a photonic crystal. Reflectance spectroscopy, in conjunction with appropriate theoretical models, was
used to determine that the germanium photonic crystal had a refractive index contrast of 2.05, the largest
refractive index contrast obtained to date for any nanoparticle-based system.
R.G. Shimmin (UIUC), R. Vajtai (RPI), R.W. Siegel (RPI), P.V. Braun (UIUC), “Room-Temperature Assembly of Germanium Photonic Crystals through Colloidal
Crystal Templating”, Chem. Mater., 2007, ASAP Article, DOI: 10.1021/cm062893l.
                Nanoscience and Engineering Center (NSEC) for Directed Assembly of Nanostructures
                          Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573

Rensselaer NSEC 0117792 - Chain Conformations and Bound Layer Correlations in Polymer Nanocomposites
A combined experimental and theoretical approach (Kumar, Schweizer) has been
employed to address the open question of chain conformation and adsorption in polymer
nanocomposites. Small angle neutron scattering (SANS) on mixtures of polystyrene and
nanosilica has unequivocally shown that polymers adopt random coil shapes, whose sizes
are independent of molecular weight and nanofiller concentration.
                                       Our novel microscopic statistical mechanical theory of
                                       polymer nanocomposites also predicts the existence of a thin
                                       thermodynamically stable bound layer of polymer
                                       surrounding dispersed fillers. The experimental polymer
                                       scattering signature of this phenomenon is a peak in the
                                       SANS spectrum, whose intensity and location are controlled
                                       by nanoparticle size and volume fraction. The neutron data
                                       are consistent with these predictions thereby providing the
                                       first evidence for the existence of nanoscopic layers that play
                                       a critical role in promoting miscibility and good filler
                                       dispersion.
 Figure 4. Schematic of fillers with
 bound polymer layers dispersed in     S. Sen (RPI), Y. Xie (RPI), S.K. Kumar (RPI), H. Yang (RPI), A. Bansal (GE), D.L. Ho
 a homopolymer matrix.                 (NIST), L. Hall (UIUC), J.B. Hooper (UIUC) and K.S. Schweizer (UIUC), “Chain
                                       Conformations and Bound Layer Correlations in Polymer Nanocomposites”, Physical
                                       Review Letters, 98, 128302 (2007).
                                         Nanoscience and Engineering Center (NSEC) for Directed
                                                       Assembly of Nanostructures
                                      Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573




Figure 5. Enzyme-catalyzed directed assembly of organogels. Lipase catalysis in acetone results in a region-selective and symmetrical
diester of the sugar trehalose. The sugar derivatives undergo self-assembly to yield nanoscale fibers that trap organic solvent molecules.
Acrylate derivatives can be polymerized to yield crosslinked hydrogel materials.
                                                         Rensselaer NSEC 0117792 - Enzyme-catalyzed Directed Assembly of Organogels
                                    Nanoscience and Engineering Center (NSEC) for Directed
                                                  Assembly of Nanostructures
                                 Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573




Organogelators with excellent ability to gel a broad range of organic solvents as well as
natural oils (olive and vegetable oils) were synthesized (Dordick) using all natural building
blocks (sugars, fatty acids, and enzymes). This is an example of exquisitely selective
enzyme-catalyzed directed assembly - chemical synthesis of the gelators results in poor gel
properties due to the lack of selectivity. With their ability to assemble at the nanoscale, and
to be prepared from all natural building blocks (sugars, fatty acids, and enzymes), these
gelators may be used to encapsulate pharma-ceutical, food, and cosmetic products and to
build 3-D biological scaffolds for tissue engineering.




G. John (CUNY), G. Zhu (RPI), J. Li (USM), and J.S. Dordick (RPI), “Enzymatically Derived Sugar-Containing Self-Assembled
Organogels with Nanostructured Morphologies”, Angew. Chem. Int. Ed. Engl. 45, 4772-4775 (2006, Cover Article).




                                                      Rensselaer NSEC 0117792 - Enzyme-catalyzed Directed Assembly of Organogels (Cont.)
                                  Nanoscience and Engineering Center (NSEC) for Directed Assembly of
                                                            Nanostructures
                                    Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573




                                                                          Nanocomposites have been developed that have
                                                                          enhanced biocompatibility while still exhibiting
                                                                          important properties associated with nanomaterials
                                                                          (Linhardt, Ajayan). Nanoporous cellulose-heparin
                                                                          composites were prepared as blood compatible
                                                                          membranes for kidney dialysis and as electrospun
                                                                          fibers for woven vascular grafts. Of significant
                                                                          interest in combining biological and materials
                                                                          applications, cellulose-oriented carbon nanotube
                                                                          composites have been prepared, which contain
                                                                          ionic liquids as batteries and supercapacitors and a
                                                                          patent application filed. These flexible,
Figure 6. Multi-wall carbon nanotubes aligned in cellulose and with
room temperature ionic liquids as a conductive medium result in           biocompatible devices are being evaluated in a
unique flexible batteries.                                                number of applications such as implantable and
                                                                          wearable power sources for medical assist devices.

S. Murugesan (RPI), S. Mousa (RPI), A. Vijayaraghavan (RPI), P.M. Ajayan (RPI), and R.J. Linhardt (RPI), “Ionic liquid derived blood
compatible composite membranes for kidney dialysis”, J. Biomed. Mat. Res. Part B - Appl. Biomater. 79B, 298-304 (2006).

G. Viswanathan (RPI), S. Murugesan (RPI), V. Pushparaj (RPI), O. Nalamasu (RPI), P.M. Ajayan (RPI), and R.J. Linhardt (RPI),
“Preparation of biopolymer fibers using electrospinning from room temperature ionic liquids”, Biomacromol. 7, 415-418 (2006).



                                               Rensselaer NSEC 0117792 - Cellulose Nanotube Composites as Flexible Power Sources
                        Nanoscience and Engineering Center (NSEC) for Directed
                                      Assembly of Nanostructures
                         Richard Siegel, Rensselaer Polytechnic Institute , DMR
                                               0642573                The Associated Press declares, “this
                                                                 high-octane show is a new answer to a
                                                                 question dogging many educators: How
                                                                 do you get young kids interested in
                                                                 science?” Independent assessment at the
                                                                 Chabot Space and Science Center in
                                                                 Oakland CA, including 1,172 viewers,
                                                                 confirms that people of all ages enjoy
                                                                 and learn from Molecularium: Riding
                                                                 Snowflakes (Garde, Schadler, Siegel).
                                                                 Key findings include the following.
                                                                 • Over 75% of viewers rated the show an 8 out
                                                                 of 10 or higher, with 63% giving the show a 10
                                                                 out of 10.

                                                                 • Across all age groups, the total percentages of
                                                                 correct answers increased significantly after
                                                                 having watched the show, while incorrect and
                                                                 “not sure” answers decreased significantly.

                                                                 • With younger audiences, the percentage of
                                                                 correct responses more than doubled after
                                                                 watching the show.
Figure 7. A digital dome screen shot from Riding Snowflakes.


                           Rensselaer NSEC 0117792 - Audiences Enriched by MoleculariumTM: Riding Snowflakes
                                      Nanoscience and Engineering Center (NSEC) for Directed Assembly of
                                                                Nanostructures
                                        Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573


                                                               Our NSEC (Schadler) has co-sponsored a
                                                               Professional Leadership Series (PLS), facilitated by
                                                               the Archer Center for Student Leadership
                                                               Development (RPI), for graduate students. This
                                                               course is enjoying unprecedented success after being
                                                               offered during the Fall and Spring semesters for
                                                               nearly five years. In particular, course enrollment,
                                                               guest speaker participation, and positive assessment
                                                               have reached an all time high during the last two
                                                               semesters.
 Figure 8. In a team activity, which explores communication
 and group dynamics, students work together to construct
 specific structures based upon one team member’s
 observation of the model.

Executives from companies such as BAE Systems, Boeing, Extreme Molding, General Dynamics, GE, IBM,
Knowles Atomic Power, Rensselaer County Regional Chamber of Commerce, Saint-Gobain, and W.L. Gore
have recognized the value of this course and volunteered their time to share their perspectives on course
topics. Engineering, science, and management students are drawn to the interactive course format, which
explores the individual qualities of a leader (e.g., ethical decision making, motivation, vision) as well as the
functional capacities of leadership (e.g., effective communication, managing conflict, team development). A
recent participant shared in their assessment of the course, “[PLS] forces you to think about yourself as a
team member and enhance your own role ~ ethically and goal oriented.”
                                                                                Rensselaer NSEC 0117792 - Leadership Series Drives
                                                                                               Students’ Professional Development
Nanoscience and Engineering Center (NSEC) for Directed Assembly of         Rensselaer NSEC 0117792 - New Render Farm Built for
                          Nanostructures                                                         Visualizing Nanoscale Universe
  Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573



                                                               NSEC has built a new render farm for the
                                                               Molecularium project that is capable of creating
                                                               IMAX quality animation. A render farm is a
                                                               collection of a large number of specialized
                                                               computer systems used to produce feature length
                                                               animation. The power and size of the
                                                               Molecularium render farm places it among the top
                                                               ranks of university-based render farm facilities.
                                                               This facility includes more than 63 terabytes of
                                                               disk, 40 terabytes of back-up tape, 160 CPU
                                                               cores, and 300 gigabytes of RAM. Whereas other
                                                               university render farms are utilized for
                                                               architecture, geophysics, or purely animation and
                                                               digital media studies, the Molecularium render
                                                               farm at Rensselaer is uniquely dedicated to the
                                                               scientific visualization and animation of the
                                                               nanoscale universe (Siegel, Schadler, Garde) for
                                                               public science literacy education and research.
       Figure 9. Photo of render farm, primary systems.
                             Nanoscience and Engineering Center (NSEC) for Directed Assembly of
                                                       Nanostructures
                               Richard Siegel, Rensselaer Polytechnic Institute , DMR 0642573




                             Figure 10. Illustration of industrial belt application of new coating technology.



The unique university-industry partnership model in place at our NSEC at RPI continues to foster well-
established partnerships with leading multinational companies. Albany International, Inc. has played a key
role as one of the Center’s original industrial partners. Joint research between Rensselaer (Siegel, Schadler)
and Albany International led to polymer nanocomposites with greatly improved mechanical properties. This
has enabled Albany International to develop a new class of materials for use in coating technology and
industrial belt applications. Albany International is currently at the scale-up stage of introducing this new
product into their engineered fabrics.


                            Rensselaer NSEC 0117792 - NSEC and Albany International Joint Research Leads to New Technology

				
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