Poly(oxazolines)s with Tapered Minidendritic Side Groups. The Simplest Cylindrical Models To Investigate the Formation of Two-Dimensional and Three-Dimensional Order by Direct Visualization

Abstract

The synthesis of 2-[3,4-bis(n-alkan-1-yloxy)phenyl]-2-oxazolines with alkan = octan, decan, dodecan, and tridecan is presented. Their living cationic ring opening polymerization produces cylindrical macromolecules that self-organize in a hexagonal columnar two-dimensional phase. The structural analysis of these polymers was carried out by a combination of techniques including differential scanning calorimetry, thermal optical polarized microscopy, X-ray diffraction, transmission electron microscopy, electron diffraction, scanning force microscopy, and atomic force microscopy (AFM). The diameter of these cylindrical macromolecules ranges from 33 to 44 A, and therefore they represent the simplest cylindrical macromolecules that can be directly visualized by AFM on a surface. Preliminary experiments have demonstrated the use of these cylindrical macromolecules as models to investigate the creation of two-dimensional and three-dimensional order via direct visualization and thus they represent the simplest nonbiological systems that mimic the role played by the complexes of nucleic acids with proteins in structural analysis by direct visualization.

Characterization of different poly(2‐oxazoline) block copolymers by MALDI‐TOF MS/MS and ESI‐Q‐TOF MS/MS

“…The cationic ring opening polymerization (CROP) of 2‐oxazolines was first reported in the 1960s5–8 and the living polymerization mechanism was also confirmed by MS 9. Because of the versatility of 2‐oxazoline monomers, the synthesis of a library of well‐defined copolymers with special properties, like self‐organizing features as well as thermoresponsive behavior10–13 is possible, as a consequence, they represent ideal candidates for the concept of functional multicompartment micelles 1, 14–16…”

Poly(oxanorbornenedicarboximide)s dendronized with amphiphilic poly(alkyl ether) dendrons

“…Alternative synthesis strategies in which dendrons are attached to or grown from (a) a preformed polymer backbone may suffer from imperfections related to the structure or number of dendrons attached to the backbone. Numerous polymerization mechanisms have been successfully applied to the living or controlled polymerization of first‐ and second‐generation dendritic macromonomers, including ionic, ring‐opening, transition metal‐catalyzed, atom transfer radical (ATRP), and reversible addition‐fragmentation transfer (RAFT) polymerizations . In an exceptional case, very short dendronized polymers having a narrow distribution of molecular weights were obtained by conventional radical polymerization of bulky macromonomers .…”

Poly(2‐oxazoline): eine Polymerklasse mit vielfältigen Anwendungsmöglichkeiten

“…[93,94] Außerdem berichteten Percec et al über systematische Veränderungen der Molekülstruktur von Poly[2-{3,4-bis(n-alkoxy)phenyl}-2-oxazolinen] in Bezug auf den Polymerisationsgrad sowie die Länge der Alkoxyketten. [95,96] Die Polymere mit einer Alkoxykettenlänge von Octan bis Tridecan bildeten kolumnare hexagonale Gitter, deren Abmessungen von der Alkoxykettenlänge wie auch vom Polymerisationsgrad abhängen. [95] Im Unterschied dazu zeigten die Polymere mit Tetradecan-und Pentadecan-Alkoxyketten einen Übergang von einer dreidimensionalen kubischen Phase bei einem niedrigen Polymerisationsgrad zu einer zweidimensionalen hexagonalen kolumnaren Phase bei einem höheren Polymerisationsgrad (Abbildung 6).…”

“…[95,96] Die Polymere mit einer Alkoxykettenlänge von Octan bis Tridecan bildeten kolumnare hexagonale Gitter, deren Abmessungen von der Alkoxykettenlänge wie auch vom Polymerisationsgrad abhängen. [95] Im Unterschied dazu zeigten die Polymere mit Tetradecan-und Pentadecan-Alkoxyketten einen Übergang von einer dreidimensionalen kubischen Phase bei einem niedrigen Polymerisationsgrad zu einer zweidimensionalen hexagonalen kolumnaren Phase bei einem höheren Polymerisationsgrad (Abbildung 6). [96] Interessanterweise wurde für Polymere mit mittleren Kettenlän-gen ein thermischer Übergang zwischen den beiden Phasen beobachtet.…”