Researchers of Maragheh University Make Artificial Muscle with Memory Nanocomposites

Saturday, November 18, 2017 - 09:54

Researchers of University of Maragheh have created a kind of nanocomposite which can remember its original shape and after deformation, it returns to its original state.

According to an ISCA report, Shape-Memory Polymers (SMPs) are polymers whose qualities have been altered to give them dynamic shape "memory" properties. Using thermal or other stimuli, SMP can exhibit a radical change from a rigid polymer to a very elastic state, then back to a rigid state again. In its elastic state, it will recover its "memory" shape if left unrestrained.

The faculty member of University of Maragheh, Dr. Mohammad Sabzi explained that in comparison with synthesized shape-memory polymers, typical ones have dual memory which means they are able to memorize two states, permanent and temporary.

This work aimed to develop a facile and broadly applicable method for fabricating a multi-stimuli responsive triple-shape memory polymer (SMP). Hence, herein the SMPs were prepared through the simple physical blending of two commercially available biopolymers, poly (lactic acid) (PLA) and poly (vinyl acetate) (PVAc), in the presence of robust and conductive graphene nanoplatelets.

Interestingly, atomic force microscopy (AFM) observations and thermal analyses revealed that the presence of nanofillers led to phase separation and appearance of two well-separated transition temperatures in the blend of these two miscible polymers.

Consequently, shape memory results showed that the unfilled blend of PLA/PVAc with a single thermal transition can only show moderate heat triggered dual-shape memory behavior. While, PLA/PVAc/graphene nanocomposite blends demonstrated excellent thermally and electrically actuated triple-shape memory effects besides their remarkable dual-shape memory behavior.

In addition, electrical conductivity of the blend was enhanced by ∼14 orders of magnitude in the presence of graphene. More interestingly, electroactive shape recovery experiments exhibited that depending on the applied voltage, temporary shapes in each region of sample can be either individually or simultaneously recovered.

The result of the study is available in ACS Applied Materials & Interfaces journal.

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