Chemomechanical devices

All books, reviews, and entries on CPs describe the potential applications. Chandrasekhar and others ° have reviewed in comprehensive fashion the applications of CPs, including batteries sensors electro-optic and optical devices microwave- and conductivity-based technologies electrochromic devices electrochemomechanical and chemomechanical devices corrosion protection semiconductor, lithography, and electrically related applications— photovoltaics, heterojunction, and photoelectrochemical cells capacitors electrolytic and electroless metal plating CP-based molecular electronic devices catalysis and delivery of drugs and chemicals membranes and LEDs. 

Osada Y, Hasebe M. Electrically activated chemomechanical devices using polyelectrolyte gels. Chem Lett 1985 1285-1288. 

It is well known that polyelectrolyte gels swell, shrink or bend when DC electric current is applied [169]. These properties of gels are applicable for the construction of chemomechanical devices, artificial muscles, energy conversion systems etc. [170]. Osada and co-workers [171] have constructed an eel-like gel actuator on the basis of poly(2-acrylamido-2-methylpropane sulfonic acid) and studied its chemomechanical properties. Polyampholyte gel is bent to the cathode or anode side if it has predominantly negative or positive charges along the macromolecules (Fig. 39) [172]. As seen from Fig. 39, the amplitude of deflection is gradually decreased with the approach to the lEP. This is probably due to... 

A chemomechanical device capable of moving a load up and down automatically and repeatedly is the simplest application of electro-shrinkable gels. Thus, two pieces of water-swollen gel (10-20 g) of AMPS were placed on the two plates of a balance and a DC current (10 V) was applied to one of the pieces. The weight of the gel decreased, bringing the device out of blance. DC was now connected to the other gel and started shrinking it. Thus, the balance could oscillate many times (more than 100 times) until most of the water of the gel was consjimed. 

New synthetic methods have been investigated over the past two decades in order to design "intelligent" or "smart" materials which exhibit large property changes in response to small physical or chemical stimuli. Stimuli-responsive polymers have been studied as smart materials aiming at the applications in biomedical fields or chemomechanical devices. The representatives of the stimuli-responsive polymers are poly(jV-... 

Figure 8.83 shows the schematic construction of a chemomechanical rotor, where anisotropic expansion causes rapid bending of the film due to the sorption of water vapor from one side of the film [140]. The rotation continued until the adsorbates were completely vaporized. This moving device may become a clean and silent power source for use as a molecular engine where the chemical free adsorption energy is transduced into the mechanical work. 

This chapter deals with the photochemistry of alkenes, alkynes, dienes, polyenes, and related compounds through a choice of the literature published during the period January 2010 — December 2011. Furthermore, recently many researchers are developing the photochemistry of these compounds for energy conversion, e.g. through nanotechnology applications, such as molecular devices, chemomechanics, molecular switches, etc. This chapter also covers the nanotechnology aspects that are based upon the utilization of isomerization/electrocyclization/cycloaddition reactions of the title compounds. 

The controlled release of drugs can be realised with many types of active devices, such as mechanical and osmotic pumps, systems of controlled diffusion, chemically-controlled systems composed from bio- or non-biodegradable polymers, magnetically-controlled systems, and not in the last instance chemomechanical systems. Figure 4.39 [136, 137]. 

Devices with moving parts based on chemomechanical systems... 

Systems which develop contractile force and change their dimensions by electric stimulus enable the construction of chemomechanical electronic devices transforming chemical energy into mechanical work, and may eventually lead to approaches to... 

The electrochemical, electromechanical (and chemomechanical) properties of amorphous carbon-based actuators are derived from their molecular origin (Janes et al. 2007 Torop et al. 2009). For the same reason, the behavior of CNT-based actuators is different compared to ones based on amorphous carbon. There are two substantial differences between amorphous carbons and carbon nanotubes Firstly, CNTs have higher electrical conductivity than porous amorphous carbons due to conjugation of carbon atoms. Secondly, the specific surface area of CNTs is significantly lower compared to most representatives of amorphous carbons leading to lower specific capacitance of the actuator device (Sugino et al. 2009). 

There are many plication possibilities, including use in artificial muscles, switches, sensors, and medical devices. The chemomechanical polymer gels introduced here are discussed based on which stimulus creates the driving force. 

Researchers are facing difficulties in attempts to improve properties and response rates of chemomechanical and electrochemomechanical systems based on polymer gels or proteins for practical applications as actuators in robotics. Lack of mechanical toughness and long-term durability are other problems to be solved. The efficiency of energy conversion must also be improved. New polymers that can link reversible chemical reactions to changes in volume are required to produce electrochemomechanical devices of practical interest. From a conceptual point of view, deep discussions are required to clarify and differentiate between chemomechanical, electromechanical, electroosmotic, electrophoretic driven, and electrochemomechanical devices. The main problem is to differentiate the presence and absence of chemical reaction. 

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