End-group modified hyperbranched polyetherimides were prepared by a one-pot, two-step reaction sequence. General synthetic techniques were developed to prepare both monofunctional terminating segments and the corresponding modified polyetherimide hyperbranched polymers. Monofunctional groups were used to terminate an AB₂-type polycondensation reaction, generating capped hyperbranched polymers (HBPs). The composition and constitution of the end groups controlled the solubility and thermal properties of the HBPs. For the same polymer backbone, different end groups were able to shift the glass-transition temperature nearly 100 °C. End-group modification greatly influenced the film-forming ability of the HBPs. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 936–946, 2002

A dynamic binding mechanism allows the association of dumbbell-shaped ligand 2 with helical folded oligo(m-phenyleneethynylene)s 1 (see schematic representation). Association constants are oligomer length specific, with a maximum value for the icosamer and docosamer. These oligomers have helical conformations that are highly shape-complementary to 1; shorter and longer oligomers exhibit association constants roughly an order of magnitude smaller.

Ein dynamischer Bindungsmechanismus ermöglicht die Assoziatbildung des hantelförmigen Liganden 2 mit helicalen gefalteten Oligo(m-phenylenethinylenen) 1 (siehe Schema). Die Assoziationskonstanten hängen von der Länge des Oligomers ab, wobei man die höchsten Werte für das Icosamer und das Docosamer findet. Die Oligomere nehmen helicale Konformationen ein, die formkomplementär zu 1 sind; kürzere und längere Oligomere weisen um etwa eine Größenordnung kleinere Assoziationskonstanten auf.

The effect of pressure up to 60 kbar was measured on the luminescence peak location and efficiency for a series of methoxy phenylacetylene dendrimers (MeO). Dendrimers MeO-3, MeO-7, MeO-15, MeO-31, MeO-63, and MeO-127 were studied as neat polymers. MeO-3, MeO-15, MeO-63, and MeO-127 were also investigated in dilute solutions in poly(tert-butyl methacrylate). According to measurements of the dilute solutions, there is a charge-transfer (CT) state that, for the smaller dendrimers, lies well above the π* state; for the larger dendrimers, it is the emitting state at 1 atm. With increasing pressure, the intramolecular CT state is rapidly stabilized, so that at high pressure the emission is from this state for all dendrimers. For the neat polymers, there is an initial redshift that reverses direction at a pressure that is higher for smaller dendrimers. This reversal is attributed to intermolecular CT. There may be changes in the molecular geometry and/or relative orientation of adjacent dendrimers that tend to stabilize the intermolecular CT in the solid state. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2859–2865, 2001

Poly(ethylethylene-b-ethylene oxide) (PEE-PEO) diblock copolymers with pyridine-benzoic acid end-groups for heterodimeric hydrogen bonding were designed as a possible means to noncentrosymmetric organizations by spontaneous self-assembly. These end-functionalized polymers were synthesized by anionic living polymerization with protected initiator and terminating reagents. A series of polymeric intermediates with different end-groups was characterized by proton nuclear magnetic resonance, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and gel permeation chromatography. Preliminary studies of solid-state organization by differential scanning calorimetry and small-angle X-ray scattering provided evidence for a long-range order that was sensitive to chain length, copolymer composition, and end-group structure. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 207–219, 2000