Water-soluble poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers are high-molecular-weight nonionic surfactants

which exhibit the richest structural polymorphism in selective solvents. One of the most interesting features of the triblock copolymers is their self-association in aqueous solutions and their rich phase behavior. The microstructure resulting from the self-assembly of the triblock copolymer can vary from normal micelles in solution

through all types of normal and reverse lyotropic liquid crystals (normal micellar cubic

normal hexagonal

normal bicontinuous cubic

lamellar

reverse bicontinuous cubic

reverse hexagonal

reverse micellar cubic)

to reverse micelles

as the relative volume fraction of the apolar components increases over that of the polar components. The self-assembly properties of PEO-PPO-PEO triblock copolymer in aqueous solutions are reviewed. Experimental techniques such as scattering techniques

spectroscopy techniques

viscometer

surface tension

ultrasonic velocimetry

differential scanning calorimetry

size exclusion chromatography and transmission electron microscopy for studying self-assembly behaviors of PEO-PPO-PEO triblock copolymers are introduced. Effects of structure of the block copolymer

molecular mass

temperature

concentration and additives such as inorganic salts

alcohols

oils

surfactants

ionic liquids and different block copolymers on self-assembly behaviors are introduced. A general overview of thermodynamic theories

molecular simulations and computer simulations of block copolymer micellar systems is also presented. Current applications of block copolymer as synthesis of mesoporous materials

controlled delivery of drug agents

separation of biomacromolecules and modification are also discussed.