Hydrogels smart

Smallpox vaccine Smalt Smaltite SMA resins SMART Smart catalysts Smart gels Smart hydrogels Smart material Smart materials... 

Other examples of pH-seasitive materials such as the smart hydrogels and smart polymers have been iacluded ia other sectioas of this article. 

Smart hydrogels, 73 742-743, 747, 22 716 Smart manufacturing, 77 154 Smart materials, 22 705-722... 

The first application developed for smart hydrogels was somewhat mundane. They were used as a liner for golf shoes and in-line skates that takes the shape of the wearer s foot as the result of heat released by the foot, but researchers have envisioned a much broader and more significant number and variety of applications for such materials. Proposed applications include optical shutters actuators and sensors for chemical, heat, and electrical systems valves chemical memory systems fluid switches absorbents for chemical and petroleum spills diapers cosmetics and desalination systems. Thus far, however, the greatest interest has been in biomedical applications of hydrogels. 

Another area in which smart hydrogels are likely to find application is the development of more efficient drug delivery systems. One material that has showed promise in this held is called Pluronic-PAA. Its trade name is Smart Hydrogel . The material is a mixture of two polymers, one of which is poly(acrylic acid) (PAA), which attaches readily to other biological materials and is responsive to changes in pH. The other polymer is a copolymer of poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO). This copolymer belongs to a family of polymers known by the trade name of Pluronic polymers. 

Like most other smart materials, smart hydrogels are still at a very early stage of development. Scientists often have only minimal understanding of the processes hy which these materials work. As a result, widespread commercial applications may still he many years in the future. 

Poloxomer3 and polyacrylic acid graft copolymer (so-called Smart Hydrogel) nonbiodegradable... 

Polyacrylic acid, poloxamer Smart Hydrogel Advanced... 

Smart hydrogels have found use in bioseparation. Materials responsive to temperature were used in liquid chromatography and electrophoretic applications, to separate proteins, steroids and DNA fragments. Antibody-containing materials for the concentration of antigens were also described. 

Speed of response The response time of the smart hydrogels have to be decreased by some orders of magnitude compared with conventional gels. Fast responsive hydrogels are necessary to obtain sufficient fast cycle times. 

An often applied method for the synthesis of hydrogels, especially for applications in medicine and pharmaceutics, is based on radiochemistry. The hydrogel can be formed by irradiation of monomers, polymers dissolved in water, or polymers in dry state. Electrons of different energies or y-rays are used as high-energy radiation. The possibilities of the radiation-chemical synthesis of smart hydrogels are discussed on different examples. The technique is applied to bulk polymers, to micro- and nanogel particles, and to patterned layers on different materials. The basics and fundamentals of irradiation techniques as well as the equipment are described. 

The swelling behaviour of smart hydrogels makes them very attractive for (micro-) actuator and sensor applications. One key point in the employment of smart... 

The application of smart hydrogels in actuator or in sensor systems is possible, even if the response of the degree of swelling and other gel properties on the environmental condition is continuously. For applications it is important that the gel properties are in a strong correlation to the properties of the surrounding liquid phase. 

The swelling/shrinking rate dQ/dt and hence the response time t for any application during volume phase transitions of smart hydrogels depends on the cooperative diffusion coefficient Dcoop and on the square of their characteristic dimension /,... 

The skin effect influences the behaviour of smart hydrogels. Inducing the volume phase transition by the high concentration of a hydrophobic component or high temperature strengthens the effect. 

Acknowledgments The author thanks M. Knorgen (Martin-Luther-Universitat Halle) for the fruitful cooperation on application of NMR imaging on smart hydrogels, and R. Reichelt (West-falische Universitat Munster) for the FESEM micrograph. 

In the following, we describe a chemical sensor combining a smart hydrogel and a micro fabricated pressure sensor chip for continuously monitoring the analyte-dependent swelling of a hydrogel in aqueous solutions. 

Richter A, Ruckling D, Arndt K-F, Gehring T, Howitz S (2003) Electronically controllable microvalves based on smart hydrogels magnitudes and potential applications. J Microelec-tromech Syst 12(5) 748-753... 

Hydrogels act in biosensors not only passively as immobilization matrix but also as responsive (smart) material. Current uses for smart hydrogels in the bioanalytical and biomedical field are... 

Bio-smart hydrogels that are responsive to specific molecules (e.g. glucose, antigens) can be used as biosensors as well as in smart drug release (Brahim et al. 2002 Ulijn et al. 2007)... 

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