Use of Gold Nanorods for Fine-Tunable Strain Strengthening of Synthetic Ploy-Isoprene

The long-term goal of this exploratory study was to understand the mechanisms of strain strengthening in poly-isoprene PI matrices loaded with polystyrene PS-coated gold nanorods. Our results show that PI thin films, manufactured via dip molding, exhibit a significant increase in Youngs modulus and hardness in the presence of a block PS-PI-PS copolymer additive when the content of styrene in the block is kept at14 . In addition, tensile testing experiments have shown that the PI films prepared in the presence of the block copolymer retain their elastic behavior and overall elongation, fracturing at or above 3000 strain. Comparative mechanical studies carried out with nanoindentation, show significantly higher values of modulus and hardness in the presence of the block copolymer compared to those determined via tensile tests, leading us to determine that this increase might be a surface effect due to the percolation depth of the block copolymer within the film.Overall, our results demonstrate that the presence of the block copolymer does affect the local mechanical properties of the PI films in a significant way, and that this might become an alternative approach to finely tuning the mechanical properties of PI even in the absence of the traditionally used fillers such as carbon nanotubes.