Thermoresponsive materials

Design of Thermoresponsive Materials by ATRP of Oligo(ethylene glycol)-based (Macro)monomers... 

MA1 Maeda, T., Kanda, T., Yonekura, Y., Yamamoto, Y., and Aoyagi, T., Hydioxylated poly(A-isopropylacrylamide) as functional thermoresponsive materials. Biomacromolecules, 1, 545, 2006. 

Temperature variations may result in reversible changes in properties such as structural arrangement, size, solubihty, and shape. Many materials designed for biomedical or biotechnology appHcations are confined to a narrow temperature spectrum in order to be effective in a physiological environment. The following thermoresponsive materials are discussed in the next section poly(N-iso-propylacrylamide (PNIPAAm), polymer brushes, and shape-memory polymers. 

Cyclopentadienyl functionality (Cp) in polymers has not received as much attention in the recent literature as, for example, azides and thiols. Nevertheless, the potential for such materials to form tuneable and reversible linkages holds great promise in the design of various uniquely thermoresponsive materials. There is, however, an inherent difficulty in achieving... 

The RAFT-HDA click strategy has certainly been proven to enable highly efficient macromolecular-macromolecular conjugations to be performed under very mild conditions. It also stands as a very rare example within the field of CRP in that the functionality utilized to mediate controlled polymerization is also the same functionality that serves as the click function. As such, the technique may be termed atom economical for this very reason. Furthermore, the reversibility of such chemistry may serve as the inspiration for the development of a variety of thermoresponsive materials. 

In addition, the copolymers with a CP close to body temperature have a robust phase transition that does not significantly vary with concentration (Figure 22.14, right). As such, these copolymers of EtOx and /tPropOx are thermoresponsive materials with a robust and tunable CP, making them suitable candidates for biomedical applications as alternatives to PNIPAM. 

In addition to PNIPAm, other synthetic thermoresponsive materials have been developed by copolymerizing hydrophilic and hydrophobic monomers... 

In the next section, an overview of the main biomedical tpplications based on shape-changing materials in response to natural stimulus (temperature—thermoresponsive materials, pH— pH-responsive materials, and mechanical—mechano-electrical materials) will be presented. 

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