Effect of Polymer Length on the Adsorption onto Aluminogermanate Imogolite Nanotubes

Abstract

This study evidences the adsorption of model non-ionic polymers onto aluminogermanate imogolite nanotubes, an attractive porous nanofiller with potential molecular loading and release applications. We resolve the underlying mechanisms between nanotubes and polyethylene glycols with different molecular weight by means of nano-isothermal titration calorimetry. The analysis of the results provides a direct thermodynamic characterization, allowing to propose a detailed description of the energetics involved in the formation of polymer/imogolite complexes. The affinity towards the nanotube surface is enthalpy-driven and strongly depends on the polymer chain length, which significantly affects the polymer configuration and the flow properties of the resulting complexes, probed by small-angle neutron scattering and rheology, respectively. These findings open new avenues for the rational design of these hybrid mixtures for advanced applications.

pH-Responsive Gelation in Metallo-Supramolecular Polymers Based on the Protic Pyridinedicarboxamide Ligand

“…We form transient networks at a polymer concentration of φ = 10 v/w %, which is significantly above the overlap concentration of the polymer precursor. 60 Considering an entanglement molar mass (M e ) of 2 kg mol −1 for PEG at the molten state, 60,61 the effective M e at this concentration is roughly 20 kg mol −1 , which shows that some loose entanglements between long chains may also contribute to the network formation. On the one hand, employing a too long PEGNH 2 precursor could reduce the reaction efficiency and the number of ligands along chains, which could avoid network buildup upon the formation of metal−ligand associations.…”

Wet spinning imogolite nanotube fibres: an in situ process study

“…All the INT solutions used in this study were found to be shear thinning. As shown recently, 23 the viscosity of INT suspensions can be reproduced using an extended hard sphere approach based on Quemada's rheological model 24,25 which gives,where η is the shear viscosity, η ∞ is the viscosity under infinite shear stress, σ is the shear stress and σ c is a critical shear stress, which corresponds to the point where the hydrodynamic effects are comparable to Brownian motion and other interactions. The parameter χ (for which −1 ≤ χ ≤ 1) reflects the state of the suspension.…”

“…All the INT solutions used in this study were found to be shear thinning. As shown recently, 23 the viscosity of INT suspensions can be reproduced using an extended hard sphere approach based on Quemada's rheological model 24,25 which gives,…”

Development of the Sequential Binding Model and Application for Anticooperative Protein Adsorption onto Charged Dendrimers

“…The Langmuir binding model is the most common adsorption isotherm that is essential for the description of the adsorbate–adsorbent equilibrium. − Although the Langmuir model was initially developed to conceptualize the saturable adsorption of gases to solid surfaces, − its applicability has been proven in wide-ranging adsorption systems − and is important throughout modern biochemistry and pharmacology for its textbook elegance and cheap computation. , In particular, the Langmuir model has a well-defined physical basis and can be fully derived via statistical mechanics on the lattice of binding sites. , Therefore, it also serves as a platform onto which further complexity can be easily integrated to embrace new challenges from various nanostructured and porous materials.…”