Competitive Formation of Polymer−Cyclodextrin Inclusion Compounds

Abstract

The hydrophobicity of the guest polymer and also the geometrical compatibility between guest polymer cross section and cavity diameter of the host cyclodextrin (CD) play important roles in the formation of inclusion compounds (ICs) between a mixture of one or two guest polymers with one or two different types of CDs, respectively. Specific polymer-CD interactions can be distinguished when, for example, polymer A-CD IC crystals are suspended in a solution containing polymer B, and a polymer B for polymer A exchange occurs, without CD-IC dissolution, during formation of polymer B-CD IC. When using the polymer pair poly( -caprolactone) (PCL)/poly(L-lactic acid) (PLLA), we have observed that PLLA-R-CD IC is completely converted to PCL-R-CD IC, while the reverse polymer transfer is almost completely prohibited. R-CD host molecules also preferentially included PCL chains from a common PCL/PLLA solution. In addition, observation of the transfer of PCL from PCL-γ-CD IC crystals suspended in a solution containing R-CD to form PCL-R-CD IC crystals now suspended in a solution containing γ-CD, while not observing the reverse transfer, has implications for the relative strength of polymer T polymer and polymer T CD interactions. Single and pairs of side-by-side parallel PCL chains occupy the channels of PCL-R-CD IC and PCL-γ-CD IC crystals, respectively, so our observations suggest that interactions between included PCL chains, which are only possible in PCL-γ-CD IC, do not lead to an increased stability for polymer-CD ICs.

Star-Pseudopolyrotaxane Organized in Nanoplatelets for Poly(ε-caprolactone)-Based Nanofibrous Scaffolds with Enhanced Surface Reactivity

“…[12][13][14][15] These crystal domains make the pPRs insoluble in most common solvents. [16][17][18] Additionally, the few known solvents able to solubilize pPRs, such as dimethyl sulfoxide (DMSO) or ionic solvents, [ 19 ] generally also destabilize the supramolecular assembly due to cyclodextrin dethreading.…”

Stereoselective Complex Formation between Polybutadiene and Cyclodextrins in Bulk

“…[1,2] Cyclodextrins (CDs) form inclusion complexes with some organic polymers, [3][4][5][6] such as poly(ethylene glycol), poly(propylene glycol), [7,8] polyesters, [9][10][11] poly(propylene)s, [12] poly(methyl vinyl ether), [13] polyamine, [14] poly(dimethylsiloxane)s, [15] poly(dimethylsilane)s, [16] polyisoprene, [17] and poly(methyl acrylate), [18] to…”

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

“…[18,19,21,41] In general, the type of guest molecule and experimental conditions determine the packing type, described as cage or channel structures. [42] For a long-chain molecule guest, the inclusion complexes were found to adopt a head-to-head channel-type structure in which cyclodextrin molecules are stacked along an axis to form a cylinder. In fact, the channel-type structure, without any included guests other than water of hydration, can also be obtained through an appropriate recrystallization process.…”

“…Therefore, even when there are no guest molecules included other than water, the channel structure consisting of endless columns of stacked CD molecules connected to each other by hydrogen bonds has been proved to be a stable structure. [42] The hydrogen bonds between hydroxyl groups of neighboring CD molecules were mediated by water molecules. [41] There is credible evidence that the hydrogen bonds between CDs play an important role in stabilizing the complexes.…”