Molecular function external field control

Organic molecules have useful optical and electronic functions that can be easily controlled by the structure, substituent, or external fields. Molecular interactions and organized molecular assemblies also can afford much higher functions than isolated or randomly distributed molecules. Photons have many superior properties such as wavelength, polarization, phase, ultrashort pulse, or parallel processability. Through interactions of molecules or molecular assemblies with photons, many properties of photons can be directly converted to changes in physical properties of materials such as fluorescence, absorption,... 

In summary, the turnstile represents a new example of rotation in a molecular system. The fact that phenylacetylene macrocycles form discotic liquid crystals suggests the possibility that turnstiles might function as discotic ferroelectric liquid crystals [34]. A dipole appropriately incorporated on the spindle might allow for its own rotation to be controlled rapidly and reversibly by an external field. 

Ultrasound-Assisted Reconstruction of Fiber Networks Besides thermodynamic control and additive-mediated formation of fiber networks, exposure of external fields in the molecular self-assembly process is another promising strategy for creating innovative supramolecular materials and systems with dynamically controlled property/functionality. The substantial interest in stimuli-responsive assembly of small molecules shown in recent years has led to the birth of new interdisciplinary research areas in the development of supramolecular materials with dynamically controlled fluidity, viscoelasticity, solvent volatility, optical transmission, ion transport, wettability, and other physical properties [6-8,11]. 

These results pave the way to functional nanoparticles where the size, shape, and iron oxide concentration can be controlled leading to tunable magnetic and optical properties of nanostructures on surfaces and interesting research in catalysis, molecular labeling, and detection, as well as controlled dmg delivery using external magnetic fields. 

The great demand for miniaturization of components in electrotechnical, medicinal or material applications has led to the development of a highly multidisciplinary scientific and technological field called nanotechnology to produce devices with critical dimensions within the range 1 100 nm. The ultimate solution to miniaturization is logically a functional molecular machine, an assembly of components capable of performing mechanical motions (rotation or linear translation) upon external stimulation, such as photoactivation.1103,1104,1239-1244 This motion should be controllable, efficient and occur periodically within an appropriate time-scale therefore, it involves photochromic behaviour discussed in the Special Topic 6.15. Such devices can also be called photochemical switches (Special Topics 6.18 and 6.15). Here we show two examples of molecular machines a molecular rotary motor and a molecular shuttle. 

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