Search results for "nanotube"

ORGANIC-INORGANIC HYBRID CATALYSTS BASED ON IMIDAZOLIUM AND THIAZOLIUM SALTS

In the last years, great attention was focused on immobilized ionic liquids for their application in the field of catalysis. The main challenge is represented by the possibility of combining the benefits of the ionic liquids to that of the supports. In order to achieve this ambitious objective both the choice of the support and the functionalization strategy are of fundamental importance. In this context, one of the aims of this doctoral project was to develop novel catalysts based on covalently mono- or multilayer imidazolium or thiazolium networks onto a high ordered mesoporous silica or carbon nanotubes materials. The second goal of this PhD thesis was to design novel imidazolium based c…

Lipid Bilayer Interactions of Peptidic Supramolecular Polymers and Their Impact on Membrane Permeability and Stability.

2020

The synthesis and physicochemical characterization of supramolecular polymers with tunable assembly profiles offer exciting opportunities, involving the development of new biomedical carriers. Because synthetic nanocarriers aim to transport substances across or toward cellular membranes, we evaluated the interactions of amphiphilic peptide-based supramolecular polymers with lipid bilayers. Here, we focused on nanorod-like supramolecular polymers, obtained from two C3-symmetric dendritic peptide amphiphiles with alternating Phe/His sequences, equipped with a peripheral tetraethylene glycol dendron (C3-PH) or charged ethylenediamine end groups (C3-PH+). Triggered by pH changes, these amphiphi…

Unraveling In vivo brain transport of protein‐coated fluorescent nanodiamonds

2019

The blood–brain barrier is the biggest hurdle to overcome for the treatment of neurological disorders. Here, protein‐coated nanodiamonds are delivered to the brain and taken up by neurovascular unit cells after intravenous injection. Thus, for the first time, nanodiamonds with their unique properties and a flexible protein coating for the attachment of therapeutics emerge as a potential platform for nanotheranostics of neurological disorders.Nanotheranostics, combining diagnostics and therapy, has the potential to revolutionize treatment of neurological disorders. But one of the major obstacles for treating central nervous system diseases is the blood–brain barrier (BBB) preventing systemic…

Novel Lipid and Polymeric Materials as Delivery Systems for Nucleic Acid Based Drugs

2015

Nucleic acid based drugs (NADBs) are short DNA/RNA molecules that include among others, antisense oligonucleotides, aptamers, small interfering RNAs and micro-interfering RNAs. Despite the different mechanisms of actions, NABDs have the ability to combat the effects of pathological gene expression in many experimental systems. Thus, nowadays, NABDs are considered to have a great therapeutic potential, possibly superior to that of available drugs. Unfortunately, however, the lack of effective delivery systems limits the practical use of NABDs. Due to their hydrophilic nature, NABDs cannot efficiently cross cellular membrane; in addition, they are subjected to fast degradation by cellular and…

Electrosynthesis of Ce–Co Mixed Oxide Nanotubes with High Aspect Ratio and Tunable Composition

2008

Cerium oxide and cobalt oxides have attracted the interest of several researchers due to their potential application in several technological fields electrochromism, lithium batteries, catalysis, etc.. Ceria has been used as a promoter in the so-called “three-way catalyst” for the control of toxic emission from automobile exhaust. The promotion consists of the enhancement of the noble metal dispersion, as well as stabilization of the supporting medium toward thermal sintering. 1,2 A direct catalytic effect of CeO2 in chemical processes such as water–gas shift reaction or NOx decomposition has been also evidenced. 3,4

CONTROLLED CHEMICAL FUNCTIONALIZATION OF CARBON NANOSTRUCTURES FOR ORGANIC PHOTOVOLTAICS AND FUNCTIONAL MATERIALS

2013

DFT calculation of structures and NMR chemical shifts of simple models of small diameter zigzag single wall carbon nanotubes (SWCNTs)

2011

Linearly conjugated benzene rings (acenes), belt-shape molecules (cyclic acenes) and model single wall carbon nanotubes (SWCNTs) were fully optimized at the unrestricted level of density functional theory (UB3LYP/6-31G*). The models of SWCNTs were selected to get some insight into the potential changes of NMR chemical shift upon systematic increase of the molecular size. The theoretical NMR chemical shifts were calculated at the B3LYP/pcS-2 level of theory using benzene as reference. In addition, the change of radial breathing mode (RBM), empirically correlated with SWCNT diameter, was directly related with the radius of cyclic acenes. Both geometrical and NMR parameters were extrapolated t…

Chemical modification of carbon nanomaterials (SWCNTs, DWCNTs, MWCNTs and SWCNHs) with diphenyl dichalcogenides

2015

Control over chemical functionalization is a crucial point in the field of nanotechnology. Herein, we present the covalent functionalization of several carbon nanoforms (single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes and carbon nanohorns) by means of diphenyl dichalcogenides. These ones show different reactivity to the nanomaterials and are able to modify their electronic properties depending on the electronegativity of the functionalizing heteroatom. Theoretical calculations were also performed to support the experimental results. All the modified structured nanocarbons were thoroughly characterized by TGA Raman, XPS, UV/Vis/nIR, IR and TEM te…

Creep and recovery of epoxy/MWCNT nanocomposites

2012

Abstract Creep and creep–recovery of epoxy/multi-wall carbon nanotube (MWCNT) composites was studied in a wide range of applied loads in order to evaluate the contribution of nanotubes on the time-dependent behaviour of the epoxy matrix. Incorporation of up to 1 wt.% of C150P MWCNTs has negligible influence on the elastic, viscoelastic and viscoplastic response of the epoxy system. No systematic changes of the creep characteristics depending on the content of nanotubes are noticed in the range of stresses from 0.3 up to 0.75 from the ultimate strength. Creep resistance and recovery performance of the epoxy matrix is not negatively affected by the addition of MWCNTs and the same analytical m…

Construction of green nanostructured heterogeneous catalysts via non-covalent surface decoration of multi-walled carbon nanotubes with Pd(II) complex…

2017

Abstract Green nanostructured heterogeneous catalysts were prepared via a bottom-up strategy. Designed ligands were synthesized joining covalently an electrondeficient pyrimidine residue and a scorpiand azamacrocycle. The desired molecular properties were easily transferred to nanostructured materials in two steps: first, exploiting their spontaneous chemisorption onto multi-walled carbon nanotubes (MWCNTs) via the pyrimidinic moiety in water at room temperature, then, taking advantage of the easy coordination of Pd(II) to the azamacrocycle in the same conditions. An evenly distribution of catalytic centres was obtained on the MWCNTs surface. Catalytic properties of these materials were ass…