| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 100 === The shear-induced microphase separation and orientational transitions of diblock copolymer/nanorod blends subjected to steady shear flow, are modeled and simulated via Dissipative Particle Dynamics method. We have tailored the affinity between nanorods and diblock copolymer, and investigated three types of nanocomposites which are containing amphiphilic Janus nanorods, A-affinity nanorods and non-affinity nanorods, respectively. The aim of our present study is to understand that how these different affinity of nanorods affect the orientational transitions of nanocomposites and rheological properties.
The results show that the shear field can be used to induce lamellar phase orientational transitions, such as transverse alignment at zero shear, parallel alignment at low shear rate and perpendicular alignment at high shear rate. The presence of nanorods delays or advances the shear-thinning phenomenon. Especially, since amphiphilic Janus nanorods tend to anchor at the interface of microphase separation, it can attract both blocks of diblock copolymer, therefore increase the viscosity of nanocomposites. Our simulations provide a possible approach to enhance the mechanical and processing properties by applying shear field and adding nanorods, that might help us study further the application of nanocomposites in the future.
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