Search results
Results From The WOW.Com Content Network
Due to this property, amphiphilic block copolymers have garnered much attention in research on vehicles for drug delivery. [39] [40] Similarly, amphiphilic block copolymers can be used for the removal of organic contaminants from water either through micelle formation [2] or film preparation. [41]
Often, amphiphilic species have several lipophilic parts, several hydrophilic parts, or several of both. Proteins and some block copolymers are such examples. [citation needed] Amphiphilic compounds have lipophilic (typically hydrocarbon) structures and hydrophilic polar functional groups (either ionic or uncharged). [citation needed]
Surfactant molecules have a molecular weight which is generally of a few hundreds of grams per mole while block copolymers are generally one or two orders of magnitude larger. Moreover, thanks to the larger hydrophilic and hydrophobic parts, block copolymers can have a much more pronounced amphiphilic nature when compared to surfactant molecules.
The addition of an amphiphilic block copolymer effectively lowers this critical micelle concentration by shifting the monomer exchange equilibrium. [2] These carriers are comparable to liposomes, however the lack of an aqueous core makes polymeric micelles less accommodating to a wide variety of drugs.
The term "polymersome" for vesicles made from block copolymers was coined in 1999. [1] Polymersomes are similar to liposomes, which are vesicles formed from naturally occurring lipids. While having many of the properties of natural liposomes, polymersomes exhibit increased stability and reduced permeability.
For the generic term poloxamer, these copolymers are commonly named with the letter P (for poloxamer) followed by three digits: the first two digits multiplied by 100 give the approximate molecular mass of the polyoxypropylene core, and the last digit multiplied by 10 gives the percentage polyoxyethylene content (e.g. P407 = poloxamer with a ...
This behavior can occur with linear block copolymers. If the different blocks of the copolymer have different properties, they can form micelles with one type of block on the inside and one type on the outside. For example, in water the hydrophobic blocks of a copolymer could end up on the inside of a micelle, with hydrophilic blocks on the ...
PEG has been used as the hydrophilic block of amphiphilic block copolymers used to create some polymersomes. [18] PEG is a component of the propellent used in UGM-133M Trident II Missiles, in service with the United States Navy. [19] PEG has been used as a solvent for aryl thioether synthesis. [20]