Supramolecular aggregations through the inclusion complexation of cyclodextrins and polymers with bulky end groups

Abstract

Mono-polyhedral oligomeric sillsesquioxane-end capped poly(e-caprolactone) (mPPCL) can form inclusion complexes (ICs) with a-and c-cyclodextrins (CDs) but not with b-CD. These CD ICs have been characterized with X-ray diffraction, solid-state 13 C cross-polarization/magic-angle-spinning NMR spectroscopy, 1 H NMR spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. The poly(e-caprolactone) (PCL) chain of mPPCL is included within the channel provided by the CDs to form a columnar, crystalline structure. The PCL/CD ratios determined by 1 H NMR spectroscopy for the ICs with a-or c-CDs are higher than the stoichiometries because of the steric hindrance of the bulky polyhedral oligomeric silsesquioxane chain end and result in a fraction of the e-caprolactone units free from complexation with the CDs. On the basis of these analyses, we propose some possible structures for these CD/mPPCL ICs. V V C 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 125-135, 2007 a Degradation temperature for free CDs and mPPCL (taken from TGA curves showing a 5% mass loss at each step of degradation under nitrogen). b Degradation temperature for the components in the CD/mPPCL complexes (taken from TGA curves showing a 5% mass loss at each step of degradation under nitrogen).

Star-Shaped and Linear POSS-Polylactide Hybrid Copolymers

“…Literature data, including our own results, point to hydroxyl and amino-functionalized POSS as the effective initiators of lactide and lactone polymerization [9,12,17,18,23,24]. Mono-functionalized hydroxyalkyl POSS molecules were typically made by a corner-capping reaction of incompletely condensed heptaisobutyl POSS trisilanols with e.g., hydroxyalkyltrichlorosilanes [18] or 2-(trichlorosilyl)ethyl acetate, followed by hydrolysis of the relevant ester and yielding mono-hydroxylalkyl derivatives of POSS [23].…”

Polyfluorene copolymer with a multiply blocked rotaxane architecture in the main chain: Synthesis and characterization

“…CDs and their chemically modified derivatives have been used as building blocks for the construction of the most diverse supramolecular architectures 1–7. It is well known that CDs form inclusion complexes with a variety of compounds by including them in their cavities 8, 9. The synthesis of such structures is based on the molecular recognition principle and is a result of the cooperation of various noncovalent interactions.…”

Organic–inorganic hybrid brushes consisting of macrocyclic oligomeric silsesquioxane and poly(ε‐caprolactone): Synthesis, characterization, and supramolecular inclusion complexation with α‐cyclodextrin

“…Stereoregular oligomeric clusters containing silicon and oxygen have recently emerged as a class of new building blocks for network solids21–26 and inorganic–organic hybrid materials 27–40. Of them, polyhedral oligomeric silsesquioxanes (POSS) have been extensively investigated.…”

“…Of them, polyhedral oligomeric silsesquioxanes (POSS) have been extensively investigated. The Si/O clusters can be used to access advanced materials owing mainly to their elemental and structural features: (i) organic–inorganic hybrid assembly together with reactive functional groups, which endows them with a good affinity with organic and inorganic materials and (ii) rigid stereoregular nanostructures, with which the Si/O clusters can be used as the nanoreinforcement agent of composites 27–41. Polymers incorporated with the well‐defined nanosized POSS (and/or spherosilicates) cages represent a class of important organic–inorganic nanocomposites 29.…”