Responsive microcapsule reactors based on hydrogen-bonded tannic acid layer-by-layer assemblies

Abstract

We explore responsive properties of hollow multilayer shells of tannic acid assembled with a range of neutral polymers, poly(N-vinylpyrrolidone) (PVPON), poly(N-vinylcaprolactam) (PVCL) or poly(N-isopropylacrylamide) (PNIPAM). We found that properties of the nanoscale shells fabricated through hydrogen-bonded layer-by-layer (LbL) assembly can be tuned changing the interaction strength of a neutral polymer with tannic acid, and by a change in counterpart hydrophobicity. Unlike most hydrogen-bonded LbL films with two polymer components, the produced tannic acid-based multilayer shells are extremely stable in the wide pH range from 2 to 10. We demonstrate that gold nanoparticles can be grown within tannic acid-containing shell walls under mild environmental conditions paving the way for further modification of the capsule walls through thiol-based surface chemistry. Moreover, these shells show reversible pH-triggered changes in surface charge and permeability towards FITC-labeled polysaccharide molecules. The permeability of these LbL containers can be controlled by changing pH providing an opportunity for loading and release of a functional cargo under mild conditions.

Layer-by-layer assembly of thin organic films on PTFE activated by cold atmospheric plasma

“…The appearance of a new band at 2632 cm -1 in the spectra of the multilayer, which is assigned to N-H stretching vibrations, also indicates the formation of intermolecular hydrogen bonds. On the other hand, the bands appearing in the 3180-3400 cm -1 spectral region are identified as the O-H stretching bands for the phenolic groups [22,30]. It can be also noticed that the absorption band of the hydroxyl groups in the TAN shifts from 3334 to 3280 cm -1 (Fig.…”

“…On the other hand, tannin coatings can exhibit antibacterial, antimutagenic or antimicrobial effects [18][19][20]. There has also been an increasing interest in H-bonded assembly of tannic acid with several neutral polymers, including poly(Nvinylpyrrolidone), for the development of physiologically stable thin films and hollow capsules for controlled drug release (since tannin can be a model polyphenolic drug) and other biotechnology applications [21][22][23][24].…”

Enhanced catalytic application of Au@polyphenol-metal nanocomposites synthesized by a facile and green method

“…The disparity in shell thickness may be ascribed to the different molecular weight of various PPs. 27 This demonstrated the general applicability of this method in the engineering of Au-based coreshell catalysts.…”

Fabrication of Ultrathin Membrane via Layer-by-Layer Self-assembly Driven by Hydrophobic Interaction Towards High Separation Performance

“…It was shown in Figure 6a−e that there was no apparent boundary between the active layer and the support layer, which could be ascribed to the infiltration of coating solution into the nanopores of support layer. Figure 6f showed that the membrane thickness exhibited a rapid growth 12,13 and increased from 43 nm to 171 nm with the bilayer number increasing from 0.5 to 5.5. A similar result was also obtained in the LbL self-assembly of epigallocatechin gallate (EGCG) with gelatin (Type A).…”

“…10 With the development of LbL self-assembly technique, diverse functions and properties are often demanded for multilayer films, which require a broader range of components beyond charged species. As a result, constructing multilayer films on the basis of non-electrostatic interactions such as hydrophobic interaction, 11 hydrogen bond, 12,13 and metal−ligand coordination 6,9 has gained more and more attention. 8 Hydrophobic interaction refers to the interaction formed between hydrophobic groups in an aqueous environment under enthalpy effect and entropy effect, which makes the hydrophobic groups cluster to reduce their exposure to water molecules.…”