Stimuli-responsive materials functions

In a more general way, the two major driving forces for the design of novel micellar systems are the control over morphology (spheres, vesicles, rods, tubules etc. with controlled size) and function (stimulus-responsive materials, biological functions). Both of these aspects are intimately related since a given morphology can induce a specific function. 

Thus we see that the stimulus-response technique using a step or pulse input function provides a convenient experimental technique for finding the age distribution of the contents and the residence-time distribution of material passing through a closed vessel. 

In most cases, the as-obtained nanocarriers can release the loaded biomolecules in response to only one kind of external stimulus, such as light, pH, or temperature, and realize a monoresponsive nanochannel. However, the sensitivity of these nanocarriers is not very efficient. Even for NIR-triggered phototherapy, the effective penetration depth of NIR light is still limited to no more than 1 cm and its sensitivity and accuracy to treat tumors located deep inside the body is thus limited. Therefore, delivery systems triggered by at least two different inputs have recently been considered by researchers. Generally, in order to get dual-responsive nanocarriers, two kinds of smart materials or one material with two functional groups must be included in the same NP. For example, two kinds of responsive materials, such as PAA and PNIPAm, can be simultaneously employed in the a pH- and... 

Natural peptide-based material Stimulus Response Function... 

Abstract To appreciate the technological potential of controlled molecular-level motion one only has to consider that it lies at the heart of virtually every biological process. When we learn how to build synthetic molecular motors and machines that can interface their effects directly with other molecular-level sub-structures and the outside world it will add a new dimension to functional molecule and materials design. In this review we discuss both the influence of chirality on the design of molecular level machines and, in turn, how molecular level machines can control the expression of chirality of a physical response to an inherently achiral stimulus. 

These concepts were first developed and described by Lehn [67] and Giuseppone [11]. The constitutional recomposition of a dynamic library of imines can display complex behavior under the effect of two external parameters a physical (T) stimulus and a chemical effector ([H+]) [67]. These results illustrate the possibility of modulating an optical by constitutional recomposition induced by a specific trigger. Such features have been used for the development of stimuli-responsive, functional dynamic materials. 

Sensitivity plays a pivotal role in explosives technology, because on the one hand it is indicative of the hazards associated with handling a material, and on the other hand it is a key parameter determining the effectiveness of an explosive in an explosive train. In the former case occurrences of low probability are of interest, while in the latter case reliable functioning of an azide demands certainty that it will detonate in response to a given stimulus. 

Another remarkable feature of responsive polymeric systems is that interactions on the molecular scale (the stimulus of some sort) lead to macroscopically detectable changes that are finally employed for the function (e.g., directed delivery of drugs). As the molecular-scale interactions and macroscopic function are so intimately linked it is noteworthy that rather few studies have dealt with the nanoscopic level of these materials. This may be due to the fact that many conventional methods of physical polymer characterization may simply not be able to resolve the many different, often counteracting interactions [18, 49, 50]. In processes like a response of any kind, solvent-polymer, solvent-solvent, and polymer-polymer interactions all play a cmcial role. Better understanding of the structure and interactions on the nanoscale is not only of value in itself but it may also shed light on similar processes in biomacromolecules and may aid the design and control of responsive polymers with respect to their applications [8, 48, 49]. These applications can be counted to the above-mentioned societal need of health, as responsive polymers are hot candidates for, e.g., drug or nucleic acid delivery purposes. 

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