Research Interests
Irreversible microdeformation mechanisms; pressure effects
on morphology and mechanical properties; relationships
between hierarchical structure and mechanical function;
mechanical properties of soft connective tissue; polymer
composites and blends; polymerization and crystallization on
crystalline surfaces; viscoelastic properties of polymer
melts; damage and fracture analysis of polymers and their
composites. Structure-property relationships in biological
systems.
Overview of Research
Our interests focus on the relationships between
hierarchical structure and mechanical function of polymeric
materials. Hierarchical structure in biocomposite systems
such as in collagenous connective tissue has many scales or
levels, and there are highly specific interactions between
these levels. We were among the first to demonstrate that
the hierarchical architecture is designed to accommodate a
complex spectrum of mechanical property requirements. The
hierarchical structure-property relationships have been
described in several soft connective tissues: tendon,
intestine and invertebral disc. Numerous levels of
organization are found with highly specific
interconnectivity and unique architectures designed to give
the required spectrum of properties for each oriented
composite system. From these lessons in biology, the laws of
complex composite systems for functional macromolecular
assemblies are considered.
Current Activity
The recent focus of the research activities has been on the
characterization and solid state properties of complex
polymeric materials including their blends and composites.
These systems have been treated as hierarchical structures
with emphasis on scaling phenomena, the interactions between
scales, and the specific architectures of the components. In
particular, new microlayered and nanolayered components have
been produced with hundreds or even thousands of alternating
layers. Recent work has also been focused in the area of
micromechanics. Interactive models have been developed to
explain toughness enhancement as a result of cooperative
crazing and shear banding. As a result, new insights have
been developed in the area of rubber toughening of amorphous
thermoplastics and reinforced layered structures. In
addition, analytical models have been created for
microlayered systems that interdiffuse and concurrently
crystallize.
Recent Publications
“Buckling in Elastomer/Plastic/Elastomer 3-Layer Films,”
Y. Hu, A. Hiltner and E. Baer, J. Polym. Composites,
25, 653 (2004).
“Free Volume and Oxygen Transport in Cold-Drawn Polyesters,”
R.Y.F. Liu and A. Hiltner, and E.Baer, J. Poly.Sci.:
Part B: Polm. Sci.: Part B: Polym. Physics, 42, 493
(2004).
“Basic Aspects of Microindentation in Multi-Layered
Poly(ethylene terephthalate)/ Polycarbonate,I.Puente Orench,”
F. Ania, A. Hiltner, T. Bernal and F.J. Balta Calleja, and
E. Baer, FILMS, Philosophical Magazine, 84, 1841,
June 2004.
“Nano and Microlayered Polymers: Structure and Properties,”
Chapter 15, p. 629, title of book: Mechanical Properties
of Polymers Based on Nanostructure and Morphology,
T.E.Bernal-Lara, A. Ranade, A. Hiltner,and E. Baer,
edited by G.H. Michler and F.J.Balta Calleja , published by
Marcel Dekker (2004).
“Photopatternable Reflective Films Producedby Nanolayer
Extrusion,” R. Tangirala, A. Hiltner, C.Weder and E.
Baer, J. Advanced Functional Materials, 14, 595,
(2004).
“Poly(ethylene Terephthalate) Modified with Aromatic
Bisester Diamides: Thermal and Oxygen Barrier Properties,”
M.R. Hibbs, J. Holtzclaw, D.M. Collard, Y Liu, A.
Hiltner,
D.A. Schiraldi, and E. Baer, J. Polym. Sci. A: Polym.
Chem.42, 1668 (2004).
“Interphase Materials by Forced-Assembly of Glassy
Polymers,” R.Y.F. Liu, T.E. Bernal-Lara, A. Hiltner and E.
Baer, Macromolecules, 37, 6972 (2004).
“Structure-Property Relationships in Coextruded Foam/Film
Microlayers, J. A.P. Ranade, A. Hiltner, D.G. Bland
and E. Baer, Cellular Plastics, 40, 497 (2004).
“Micromechanical Processes in PET/PC Multilayered Tapes:
High Voltage Electron Microscopy Investigations,” E.M. Ivan
‘Kova, G.H. Michler, A. Hiltner and E. Baer, Macromol.
Mater. Eng. 289, 787 (2004).
“Effect of Orientation on the Free Volume and Oxygen
Transport of a Polypropylene Copolymer,” L.S. Somlai,
R.Y.F. Liu, L.M. Landoll, A. Hiltner, and E. Baer J.
Polym.Sci.:Part B: Polymer Physics, 43, 1230 (2004).
“Nanostructure Development in Multilayered Polymer Systems
as Revealed by X-ray Scattering Methods,” T. Bernal
and S.S. Funari, “F.J. Balta Calleja, F. Ania, I.P. Orench,
A. Hiltner, E. Baer, Progr. in Colloid and Polym. Sci.,
130, 140 (2005).
“Effect of Water Sorption on Oxygen Barrier Properties of
Aromatic Polyamides,” Y.S. Hu, S. Mehta, D.A.
Schiraldi, A. Hiltner and E. Baer, J. Polym. Sci., Part B:
Phys., 43, 1365 (2005).
“Structure and Thermal Stability of Polyethylene Nanolayers,”
T.E. Bernal-Lara, R.Y.F. Liu, A.Hiltner, E. Baer,
POLYMER, 46, 3043 (2005).
“Improving Gas Barrier of PET by Blending with Aromatic
Polyamides,” Y.S. Hu, V. Prattipati, S.Mehta, D.S.
Schiraldi, A Hiltner, E. Baer, POLYMER, 46, 2685
(2005).
“Oxygen Transport as a Solid State Structure Probe for
Polymeric Materials: A Review,” A. Hiltner, R.Y.F. Liu,
Y.S. Hu and E.Baer, J. Polym. Sci., Part B: Phys., 43,
1047 (2005).
“Structure and Properties of Homogeneous Copolymers of
Propylene and 1-Hexene.” B. Poon, M.Rogunova,
S.P. Chum, A. Galeski, E. Piorkowska, A. Hiltner and E.
Baer, Macromolecules, 38, 1232 (2005).
“Polymer
Interphase Materials by Forced-Assembly,” R.Y.Liu, T.E.
Bernal-Lara, A. Hiltner and E.Baer, Macromolecules,
38, 4819 (2005).
“Conductivity of Polyolefins Filled with High Structure
Carbon Black,” J. Yu, L.Q. Zhang, M.Rogunova,
J. Summers, A. Hiltner and E. Baer, J. Appl. Polym. Sci.,
98, 1799 (2005).
“Improving Transparency of Stretched PET/MXD6 Blends by
Modifying PET with Isophthalate,” Y.S. Hu, V.
Prattipati, S. Mehta, A. Hiltner, and E.Baer, POLYMER 46,
5202 (2005).
“Improving Oxygen Barrier Properties of PET by Incorporating
Isophthalate: I. Effect of Orientation,” R.Y.F. Liu, Y.S.
Hu, M.R. Hibbs, D.M. Collard, D.A. Schiraldi, A. Hiltner,
and E. Baer, J. Appl. Polym. Sci., 98, 1615, 2005.
“Improving Oxygen Barrier Properties of PET by
IncorporatingIsophthalate: II. Effect of Crystallization,”
Y.S. Hu, A. Hiltner and E.Baer, J. Appl. Polym. Sci.,
98, 1629 (2005).
“Effect of Compatibilization on Oxygen Barrier Properties of
PET/MXD6 Blends,” V. Prattipati, Y.S.Hu, S. Bandi,
D.A. Schiraldi, A. Hiltner and E. Baer, J. Appl. Polym.Sci.,
97, 1361 (2005).
“Investigating Morphology and Deformation Behavior of
Multilayered PC/PET Composites,” R.Adhikari, W. Lebek, R.
Godehardt, S. Henning, G.H. Michler, A. Hiltner, and E.
Baer, J. Poly. for Adv. Technol., 16, 95, (2005).
Recent Presentations
“Polymer Nanolayered Graded Index Lenses – Lessons from
Biology,” Naval Research Lab, Washington, D.C., November 16,
2004.
“Polymer Nanolayered Graded Index Lenses – Lessons from
Biology,” Eastman Kodak Company, Rochester, New York,
November 17, 2004.
“Bio-Mimetic GRIN Lens Using Polymeric Nanolayered Film
Systems,” Materials Research Society meeting, Boston,
Massachusetts, November 29 – December 3, 2004.
“Hierarchical Biostructures and Nanolayered Systems,”
Department of Chemical Engineering, Case Western Reserve
University, January 27, 2005.
“Forced Assembly into Polymer Nanolayers: Creating Polymer
Plus,” 28th Asilomar Conference on Polymeric Materials,
Asilomar State Park, Pacific Grove, CA, February 13-16,
2005.
“Creating Polymeric Nanolayered Systems by Forced Assembly,”
Dept. of Polymer Science and Engineering, University of
Massachusetts, April 22, 2005.
“Polymeric Nanolayered Film Systems,” SPE/ANTEC 2005
meeting, Boston, Massachusetts, May 3, 2005.
“Forced Assembly into Polymer Nanolayers: Creating Polymers
Plus,” 10th Symposium on Deformation Mechanisms in Micro-
and Nanostructured Polymers, Martin Luther University, Halle,
Germany, May 19-20, 2005.
“Bio-mimetic GRIN Lenses Ujing Polymeric Nnolayered Film
Systems,” 230th ACS National Meeting, Washington, DC, August
28 – September 1, 2005.
“Solid State Dynamic GRIN Lens,” Bio-Optic Synthetic Systems
Phase II Principal Investigator Conference, Santa Fe, New
Mexico, October 25-57, 2005.
“Bio-mimetic GRIN Lens Using Polymeric Nanolayered Film
Systems,” 3M Company, St. Paul, Minnesota, November 21,
2005.
Awards
2000: Inducted into The Plastics Hall of Fame, June 22,
2000
1999: Roon Foundation Award, Federation of Societies for
Coatings Technology and Coatings Industry Education Fund
1998: Humel Hovorka Prize of CASE
1997: Paul J. Flory Education Award of the ACS
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