Search results for "Amphiphile"

Elastic Properties and Line Tension of Self-Assembled Bilayer Membranes

2013

The elastic properties of a self-assembled bilayer membrane are studied using the self-consistent field theory, applied to a model system composed of flexible amphiphilic chains dissolved in hydrophilic polymeric solvents. Examining the free energy of bilayer membranes with different geometries allows us to calculate their bending modulus, Gaussian modulus, two fourth-order membrane moduli, and the line tension. The dependence of these parameters on the microscopic characteristics of the amphiphilic chain, characterized by the volume fraction of the hydrophilic component, is systematically studied. The theoretical predictions are compared with the results from a simple monolayer model, whic…

DNA Block Copolymer Micelles – A Combinatorial Tool for Cancer Nanotechnology

2008

Selective drug targeting of a specific organ or tissue is a challenging task. This holds especially true for chemotherapeutic cancer treatment because most of the available anticancer agents cannot distinguish between cancerous and healthy cells, leading to systemic toxicity and undesirable side effects. One effective approach to address this problem is the application of polymeric nanoparticles equipped with targeting units for tumor-specific delivery. For instance dendrimers, highly branched macromolecules, can be equipped with targeting units as well as with anticancer drugs because of their large number of surface functionalities. Amphiphilic block copolymers, which self-assemble in dil…

The supramolecular self-organization of an amphotropic cholesterol derivative Micelles, liposomes and liquid-crystalline phases

1993

Abstract The cholesterol derivative tetraethoxycholesteryl semisuccinate is both a mesogen and an amphiphile. This combination of both molecular prerequisites permits two types of supramolecular self-organization: the formation of a thermotropic liquid-crystalline phase and of various forms of aggregates in contact with water or other solvents. Depending on the pH of the aqueous medium the compound self organizes in micelles or liposomes. At high concentrations lyotropic liquid-crystalline phases are obtained. The formation of liposomes and lyotropic phases is not restricted to water as a solvent but can also be induced in pure organic media such as water-free diethyleneglycol. Due to the b…

Self-assembly of amphiphilic imidazolium-based hexa-peri-hexabenzo-coronenes into fibreous aggregates

2007

Imidazolium-based amphiphilic hexa-peri-hexabenzocoronenes were synthesized and shown to undergo ordered columnar self-assembly in solid-state as well as in solution to yield defined nanofibers upon solution drop casting onto solid substrate.

Interfacial Self-Assembly of Amphiphilic Dual Temperature Responsive Actuating Janus Particles

2018

Amphiphilic polyaspartamide copolymer-based micelles for rivastigmine delivery to neuronal cells

2012

A novel polysorbate-80 (PS(80))-attached amphiphilic copolymer comprising a hydrophilic α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) backbone and hydrophobic squalenyl-C(17) (Sq(17)) portions was synthesized and characterized; the formation of polymeric micelles was also evaluated. Rivastigmine free-base (Riv), a hydrophobic drug employed to treat Alzheimer's disease, was chosen as model drug to investigate micelle's ability to incorporate hydrophobic molecules and target them to neuronal cells. Micelle formation was studied through analyses including fluorescence spectroscopy and 2D (1)H-NMR NOESY experiments. Finally, the capacity of Riv-loaded micelles, versus free drug, to penetrat…

Tradition and innovation in science

2006

A Commentary on the paper ”Self‐organization of substituted azacrowns based on their discoid and amphiphilic nature„, by C. Mertesdorf and H. Ringsdorf. First published in Liquid Crystals, 5, 1757‐1772 (1989).

New amphiphilic poly(butadiene)-graft-poly(ethylene oxide)s

1995

Amphiphilic graft copolymers with a poly(butadiene) backbone and poly(ethylene oxide) side chains were synthesized by grafting isocyanateterminated poly(ethylene oxide) on to partially hydroxylated poly(butadiene). The graft copolymers are water soluble if the fraction of hydrophilic poly(ethylene oxide) exceeds 50 wt%. Solutions of graft copolymers in water and tetrahydrofuran were studied by static light scattering and viscosity measurements. By dynamic light scattering in solution it was shown that the graft copolymers form clusters.

Polyelectrolytes on block copolymer surfaces

2004

Soft lithography and properties of amphiphilic block copolymers are combined in a new technique for the generation of patterned substrates, which can be used in different ways as templates for further processing. In these processing steps the deposition of polyelectrolytes, metals and grafting from polymerizations are used for the construction of different structures.

Poly(styrene sulfonate) self-organization: electrostatic and secondary interactions

2004

We investigate the self-organization of PSS in brushes and polyelectrolyte multilayers with X-ray, neutron and optical reflectivity. The electrostatic force dominates brush phases and adsorption behavior, additionally we find evidence of a strong hydrophobic force: (i) within amphiphilic diblock copolymer monolayers, a PSS monolayer adsorbs flatly to the hydrophobic block, (ii) on temperature increase (and with screened electrostatic forces), more PSS is adsorbed onto oppositely charged surfaces, and (iii) a polyelectrolyte multilayers shrinks when heated at 100% r.h. The latter two effects are consistent with the well-known increase of the hydrophobic force on heating: The increased PSS su…