Search results for "SUPRAMOLECULAR POLYMERS"
showing 10 items of 65 documents
New concepts and applications in macromolecular chemistry of fullerenes
2010
A new classification on the different types of fullerene-containing polymers is presented according to their different properties and applications they exhibit in a variety of fields. Because of their interest and novelty, water-soluble and biodegradable C(60)-polymers are discussed first, followed by polyfullerene-based membranes where unprecedented supramolecular structures are presented. Next are compounds that involve hybrid materials formed from fullerenes and other components such as silica, DNA, and carbon nanotubes (CNTs) where the most recent advances have been achieved. A most relevant topic is still that of C(60)-based donor-acceptor (D-A) polymers. Since their application in pho…
Deconvolution of the Effects of Binary Associations and Collective Assemblies on the Rheological Properties of Entangled Side-Chain Supramolecular Po…
2019
The properties and function of supramolecular polymer networks are determined not only by pairwise interchain transient associations but also by chain entanglement and nanoscopic phase separation of the associative groups. To unravel the impact and interplay of these different factors, we devise a set of model supramolecular polymer networks in which the number of entanglements and the density of associative groups are systematically varied. Rheological data show that by increasing the density of associative groups, the plateau modulus grows to a steady level and extends over a distinct frequency range. This is credited to the presence of binary associations with unique partner exchange tim…
Programmable assembly of peptide amphiphile via noncovalent-to-covalent bond conversion
2017
Controlling the number of monomers in a supramolecular polymer has been a great challenge in programmable self-assembly of organic molecules. One approach has been to make use of frustrated growth of the supramolecular assembly by tuning the balance of attractive and repulsive intermolecular forces. We report here on the use of covalent bond formation among monomers, compensating for intermolecular electrostatic repulsion, as a mechanism to control the length of a supramolecular nanofiber formed by self-assembly of peptide amphiphiles. Circular dichroism spectroscopy in combination with dynamic light scattering, size-exclusion chromatography, and transmittance electron microscope analyses r…
Mannose-Decorated Multicomponent Supramolecular Polymers Trigger Effective Uptake into Antigen-Presenting Cells
2018
A modular route to prepare functional self-assembling dendritic peptide amphiphiles decorated with mannosides, to effectively target antigen-presenting cells, such as macrophages, is reported. The monomeric building blocks were equipped with tetra(ethylene glycol)s (TEGs) or labeled with a Cy3 fluorescent probe. Experiments on the uptake of the multifunctional supramolecular particles into murine macrophages (Mφs) were monitored by confocal microscopy and fluorescence-activated cell sorting. Mannose-decorated supramolecular polymers trigger a significantly higher cellular uptake and distribution, relative to TEG carrying bare polymers. No cytotoxicity or negative impact on cytokine producti…
Evaluation of Charge‐Regulated Supramolecular Copolymerization to Tune the Time Scale for Oxidative Disassembly of β‐Sheet Comonomers
2019
A multistimuli-responsive supramolecular copolymerization is reported. The copolymerization is driven by hydrogen bond encoded β-sheet-based charge co-assembly into 1D nanorods in water, using glutamic acid or lysine residues in either of the peptide comonomers. The incorporation of methionine as hydrophobic amino acid supports β-sheet formation, but oxidation of the thioether side-chain to a sulfoxide functional group destabilizes the β-sheet ordered domains and induces disassembly of the supramolecular polymers. Using H2 O2 as reactive oxygen species, the time scale and kinetics of the oxidative disassembly are probed. Compared to the charge neutral homopolymers, it is found that the oxid…
Secondary Structure-Driven Hydrogelation Using Foldable Telechelic Polymer-Peptide Conjugates.
2018
The synthesis of ABA and ABA' triblock polyethylene glycol-and polysarcosine-peptide conjugates is reported. The A/A' peptides are based on phenylalanine(F)-histidine(H) pentapeptide sequences FHFHF, which promote pH-switchable β-sheet self-assembly into nanorods in water. Only parallel β-sheet-driven folding and intermolecular assembly using ABA triblock polymer-peptide conjugates leads to interstrand cross-linking and hydrogelation, highlighting the impact of supramolecular interactions-directed structure formation at the nano- and mesoscopic level.
Tuning the life-time of supramolecular hydrogels using ROS-responsive telechelic peptide-polymer conjugates
2019
Abstract The synthesis of multi-stimuli responsive peptide-poly(ethylene glycol) ABA-type conjugates is reported. The β-sheet encoded intramolecular folding and intermolecular self-assembly into 1D nanorods is based on a phenylalanine(F)-methionine(M)-histidine(H) FMHMHF hexapeptide sequence, and the supramolecular nanorods are stabilised by a shielding corona of hydrophilic PEG polymers. Interstrand crosslinking leads to the formation of physical networks and hydrogels at physiological pH and at room temperature. The thioether functional groups integrate oxidation responsive properties in the supramolecular polymer assemblies. We show that the glucose fuelled and glucose oxidase catalysed …
Learning from nature: beta-sheet-mimicking copolymers get organized.
2007
The solution structures formed by coil-coil copolymers arise from the selective solvation of one of the two blocks and have been well described. In most cases in such relatively simple synthetic structures there are no specific attractive forces that can aid the aggregation process. Nature, however, provides plenty of inspiring polymeric architectures that are shaped and ordered hierarchically by noncovalent forces. The high level of structural definition displayed by proteins, for example, is unmatched by synthetic polymers. An emerging area of interest in polymer science tries to combine the best of both worlds, the natural and the synthetic, by conjugating synthetic polymers and beta-she…
Supramolecular hierarchy among halogen and hydrogen bond donors in light-induced surface patterning
2015
Halogen bonding, a noncovalent interaction possessing several unique features compared to the more familiar hydrogen bonding, is emerging as a powerful tool in functional materials design. Herein, we unambiguously show that one of these characteristic features, namely high directionality, renders halogen bonding the interaction of choice when developing azobenzene-containing supramolecular polymers for light-induced surface patterning. The study is conducted by using an extensive library of azobenzene molecules that differ only in terms of the bond-donor unit. We introduce a new tetrafluorophenol-containing azobenzene photoswitch capable of forming strong hydrogen bonds, and show that an io…
Steric Constraints Induced Frustrated Growth of Supramolecular Nanorods in Water.
2015
A unique example of supramolecular polymerisation in water based on monomers with nanomolar affinities, which yield rod-like materials with extraordinarily high thermodynamic stability, yet of finite length, is reported. A small library of charge-neutral dendritic peptide amphiphiles was prepared, with a branched nonaphenylalanine-based core that was conjugated to hydrophilic dendrons of variable steric demand. Below a critical size of the dendron, the monomers assemble into nanorod-like polymers, whereas for larger dendritic side chains frustrated growth into near isotropic particles is observed. The supramolecular morphologies observed by electron microscopy, X-ray scattering and diffusio…