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A key goal of nanotechnology is the development of artificial machines capable of converting molecular movement into macroscopic work. Although conversion of light into shape changes has been reported and compared to artificial muscles, real applications require work against an external load. Here, we describe the design, synthesis and operation of spring-like materials capable of converting light energy into mechanical work at the macroscopic scale. These versatile materials consist of molecular switches embedded in liquid-crystalline polymer springs. In these springs, molecular movement is converted and amplified into controlled and reversible twisting motions. The springs display complex motion, which includes winding, unwinding and helix inversion, as dictated by their initial shape. Importantly, they can produce work by moving a macroscopic object and mimicking mechanical movements, such as those used by plant tendrils to help the plant access sunlight. These functional materials have potential applications in micromechanical systems, soft robotics and artificial muscles.

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Amphiphilic block copolymers containing a poly(styrene) tail and a charged helical poly(isocyanide) headgroup derived from isocyano-L-alanine-L-alanine and isocyano-L-alanine-L-histidine were prepared. Analogous to low-molecular mass surfactants, these block copolymers self-assembled in aqueous systems to form micelles, vesicles, and bilayer aggregates. The morphology of these aggregates can be controlled by variation of the length of the poly(isocyanide) block, the pH, and the anion-headgroup interactions. The chirality of the macromolecules results in the formation of helical superstructures that have a helical sense opposite to that of the constituent block copolymers. The great variety of morphologies displayed by these block copolymers and the fact that they are easily accessible from poly(styrene) and different types of peptides open new opportunities for applications in the fields of life and materials sciences.

A series of alpha-functional maleimide polymethacrylates (M(n) = 4.1-35.4 kDa, PDi = 1.06-1.27) have been prepared via copper-catalyzed living radical polymerization (LRP). Two independent synthetic protocols have been successfully developed and the polymers obtained in multigram scale, with an 80-100% content of maleimide reactive chain ends, depending on the method employed. A method for the synthesis of amino-terminated polymers, starting from Boc-protected amino initiators, has also been developed, as these derivatives are key intermediates in one of the two processes studied in the present work. The alternative synthetic pathway involves an initiator containing a maleimide unit "protected" as a Diels-Alder adduct. After the polymerization step, the maleimide functionality has been reintroduced by retro-Diels-Alder reaction, by simply refluxing those polymers in toluene for 7 h. These maleimido-terminated materials, poly(methoxyPEG((475))) methacrylates and poly(glycerol) methacrylates, differ for both the nature and size of the polymer side branches and showed an excellent solubility in water, a property that made them an ideal candidate for the synthesis of new polymer-(poly)peptide biomaterials. These functional polymers have been successfully employed in conjugation reactions in the presence of thiol-containing model substrates, namely, reduced glutathione (gamma-Glu-Cys-Gly) and the carrier protein, bovine serum albumin (BSA), in 100 mM phosphate buffer (pH 6.8-7.4) and ambient temperature.