| The application of mechanically interlocked molecules --- (i) as molecular switches in the fabrication of nanoelectronic devices, (ii) as molecular actuators for constructing artificial muscles, and (iii) in controlling the release of molecules stored in mesoporous silica nanoparticles --- remains an area of intense activity in research. The performance of these devices are governed by the switching behavior of the mechanically interlocked molecules in the different environments, such as in polymer scaffolds, on the surfaces of nanostructures, or in aqueous solutions. This Thesis describes my efforts, covering my entire graduate study, to explore switchable mechanically interlocked molecules in environments, other than traditionally in solution of organic solvents.;This Thesis begins with a brief historical introduction (Chapter 1) to the development of various kinds of mechanically interlocked macromolecules. My argument then moves on (Chapter 2) to the synthesis and investigation of a switchable, muscle-like molecular [c2]daisy chain, which undergoes extension/contraction upon the addition of acid/base. Chapter 3 relates to the incorporation of a molecular actuator into polymer chains and the switching behavior of the resulting poly[c2]daisy chains. In Chapter 4, the synthesis, characterization and self-assembly of a donor-acceptor side-chain poly[2]catenane, are outlined. Chapter 5 continues the story with a discussion of a donor-acceptor main-chain poly[n]rotaxane, which has been applied in the fabrication of electronic memory devices in the form of molecular switch tunnel junctions. The account of my graduate work continues with the physicochemical investigation of nanoparticle-conjugated molecular switches, including donor-acceptor [2]catenanes, [2]rotaxanes, and pseudorotaxanes, and is demonstrated in Chapter 6 and 7. Subsequently, Chapter 8 describes the application of a bistable [2]rotaxane to the development of active molecular plasmonics devices. Finally, the synthesis, molecular dynamics (Chapter 9), and orthogonal bistability (Chapter 10) of donor-acceptor [2]catenanes in aqueous environments are described at the end of my Thesis.;My goal in writing this Thesis has been to provide the reader with an insight into the mechanically interlocked molecular switches and to suggest how these exotic new materials might be employed in cutting-edge applications. |
