Associates / Fellows
Thieo E. Hogen-Esch
Professor of Chemistry
Polymer synthesis using anionic, radical and other controlled
Properties of Polymer Rings
vinylaromatic polymers and copolymers synthesized by anionic polymerization
followed by high dilution intramolecular coupling show properties that are distinctly
different from linear polymers of the same length. For instance cyclic poly(2-vinyl
fluorene), poly(2-vinylnaphthalene) and similar polymers or copolymers show
a fluorescence that is enhanced by up to 200 percent. compared to the linear
polymers of the same length. Very rapid intramolecular chromophore-to-chromophore
Förster energy transfer (~1 ps) has been demonstrated in some of these
polymers that have potential for light harvesting applications and this is being
explored in collaboration with the Bradforth group.
Light Emitting Polymer Systems
copolymers frequently show spatially ordered domain formation by thermodynamically
driven phase separation of polymer block at the nanoscale level (10-200 nm).
The resulting physical crosslinking of chains is of interest, for instance,
in thermoplastic elastomers and in electro-optic and other applications. For
instance we have synthesized perfluorocarbon (RF) containing self-assembling
polymers containing vinylaromatic blocks with hole and electron conducting properties.
Efficient light emitting groups positioned at the polymer-polymer block junctions.
are of interest in light emitting devices and are being investigated in collaboration
with the Thompson group.
of Polymers with Applications in Direct Oxidation Methanol Fuel Cells.
with the Olah/Prakash groups we have shown that the use of (co)polymers in direct
methanol oxidation fuel cells (DMFC’s) favorably mediates methanol utilization.
For instance undesirable “methanol cross-over” may be reduced substantially
using certain copolymers. The synthesis of new (co)polymers for DMFC’
membranes and other fuel cell applications is also a part of this program.
Properties of Novel Vinyl Copolymers.
with an industrial partner we have recently started a polymer synthesis program
aimed at exploring fundamental copolymer structure-property relationships with
respect to adhesion phenomena. This involves the synthesis and copolymerization
of so called polymerizable vinyl monomers with large hydrocarbon pendent groups
(“macromonomers”). The adhesive properties of these copolymers and
its fundamental relationship with copolymer structure and topology is the main
focus of this research.
A. Hogen-Esch; T.E. Carlotti S. “Characterization and Fluorescence
of Macrocyclic Polystyrene-2. Molecular Weight Dependent Properties”.Macromol.
Chem and Phys 2005 ,206 (10) 1034 .
J-G; Hogen-Esch, T. E. “ Synthesis and characterization of poly 2-phenyl-5-(4-vinylphenyl)-1,3,4-oxadiazole
using atom transfer radical polymerization.” Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) 2005,
R.; Nossarev, G.,G.; Hogen-Esch T. E “Synthesis and Properties of
Macrocyclic Vinylaromatic Polymers Containing a Single 1,4-Benzylidene or
9,10-Anthracenylidene Group”. Makromol. Chem. Macromol. Symp. 2004, 215, 67-79.
R. Hogen-Esch T. E. “Synthesis and Spectroscopic Studies of Macrocyclic
Poly (9,9-dimethyl-2-vinylfluorene)-b-Polystyrene Containing Single 9,10-Anthracenylidene
Linking Units” . J. Pol. Sci. A. (Chem. Ed.) 2004,
M. E.; Hogen-Esch T. E.;Thompson, M.E. "Phosphorescence Quenching by
Conjugated Polymers." J. Am. Chem. Soc. 2003,125(26),7796.
Hogen-Esch T. E. “Synthesis and Association of Poly(N,N-dimethylacrylamide)
Copolymers with Perfluorocarbon Pendent Groups Connected Through Polyethylene-glycol
Tethers”. J. Pol. Sci. A. ( Chem. Ed.) 2004,
S., Thompson M.E., Hogen-Esch T.E. “Reactive Oligomer Intermediates
In The Yamamoto Coupling Mediated Polymerization of 2,7-Dibromofluorenes.” Polymer Preprints (American Chemical Society, Division of Polymer
Chemistry) 2004, 45(2), 466.
Hogen-Esch T. E. “Poly(N,N-dimethylacrylamide) with Perfluorocarbon
Pendent Groups Connected Through Polyethylene-glycol Tethers Give Physical
Gels in Organic Solvents”. Macromolecules 2003,
R.; Zhang, X.; Hogen-Esch T. E. “Synthesis and Thermal Properties
of Macrocyclic Poly(9,9-dimethyl-2-vinylfluorene) Containing Single 1,4-Benzylidene
or 9,10-Anthracenylidene Linking Units” Macromolecules 2003,
R.; Johnson, J.; Bradforth, S.E. Hogen-Esch T. E “UV-Vis Absorption
and Fluorescence Emission Spectroscopic Studies of Macrocyclic and Linear
Poly(9,9-dimethyl-2-vinylfluorene). Evidence for Ground State Chromophore
Interactions” Macromolecules 2003, 36, 9966.
G.G.; Hogen-Esch, T. E. "Synthesis and Thermal Properties of Macrocyclic
Poly(2-vinylnaphthalene) Containing Single 1,4-Benzylidene or 9,10-Anthracenylidene
Groups" Macromolecules, 2002, 35,1604.
K. A. ; Tillman, E. ; Carlotti, S. ; King, K.; Bradforth, S. E.; Parker,
D. ; Feast, W. J.; Hogen-Esch T. E "Characterization and Fluorescence
of Macrocyclic Polystyrene by Anionic End to End Coupling. Role of Coupling
Reagents" Macromolecules, 2002, 35, 3856
Y-D and Hogen Esch T..E. "Synthesis and Characterization of Catenated
PS-Poly(2-vinylpyridine) Block Copolymers". Macromolecules 2002, 35, 7699.
G. G.; Hogen-Esch, T. E. "Living Anionic Polymerization of 2-Vinylnaphthalene
in THF in the Presence of Lithium Ion. Role of Monomer Purification" Macromolecules, 2001,34,5373.
K.; Chen R.; Hogen-Esch T.E “A New Bifunctional Initiator for use
in Anionic Polymerizations” J. Polym Sci. Part A: Polymer Chemistry, 2002, 40, 2108.