Shape memory nanocomposite of poly(L-lactic acid)/graphene nanoplatelets triggered by infrared light and thermal heating

Abstract

Abstract. In this study, the effect of graphene nanoplatelets (GNPs) on the shape memory properties of poly(L-lactic acid) (PLLA) was studied. In addition to thermal activation, the possibility of infrared actuating of thermo-responsive shape memory PLLA/GNPs nanocomposite was investigated. The incorporated GNPs were expected to absorb infrared wave's energy and activate shape memory PLLA/GNPs. Different techniques such as differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), field emission gun scanning electron microscope (FEG-SEM) and dynamic mechanical thermal analysis (DMTA) were used to characterize samples. DSC and WAXD results indicated that GNPs augmented crystallinity due to nucleating effect of graphene particles. GNPs improved both thermal and infrared activating shape memory properties along with faster response. Pure shape memory PLLA was slightly responsive to infrared light and its infrared actuated shape recovery ratio was 86% which increased to more than 95% with loading of GNPs. Drastic improvement in the crystallinity was obtained in nanocomposites with lower GNPs contents (0.5 and 1 wt%) due to finer dispersion of graphene which resulted in more prominent mechanical and shape memory properties enhancement. Infrared activated shape memory PLLA/GNPs nanocomposites can be developed for wireless remote shape control of smart medical and bio-systems.

Facile design of heat-triggered shape memory ethylene-acrylic acid copolymer/chloroprene rubber thermoplastic vulcanizates

“…The dual-shape HSMPs could be fixed in its temporary shape under an external force after cooling down to the specific deformation temperature (T d ) from the programming temperature above its T g or T m . Then temporary shape was recovered from the orientated samples while the recovery temperature (T r ) was increased again to above the T sw [19,20], which was attributed to the entropy effect because the active molecular chains energetically prefer to return to the most disordered conformation [21][22][23][24]. Typical HSMPs are usually synthetic block copolymers, in which physically or chemically crosslinked hard segments create permanent memory shape and soft segments provide switching domains [25][26][27].…”

Designing triple‐shape memory polymers from a miscible polymer pair through dual‐electrospinning technique

“…Shape memory polymers (SMPs), a class of stimuli‐responsive materials, are able to switch from temporary shape(s) to their original shape upon the application of specific external stimuli, such as heat, infrared light, electricity, radio frequency, alternating magnetic field, and solvent …”

Near‐Infrared Light Triggered Soft Actuators in Aqueous Media Prepared from Shape‐Memory Polymer Composites

“…Therefore, light‐induced SMPs provide a good choice as smart materials for light‐induced soft actuators. Recently, the mixing of photothermal fillers into heat responsive SMPs, creating light‐induced SMP composites, has been fully developed . Such SMP composites exhibit shape recovery when the indirectly generated temperature goes beyond their switching temperatures ( T sw ).…”

“…Recently, the mixing of photothermal fi llers into heat responsive SMPs, creating light-induced SMP composites, has been fully developed. [21][22][23][24][25][26] Such SMP composites exhibit shape recovery when the indirectly generated temperature goes beyond their switching temperatures ( T sw ). The light-induced heat is determined by fi ller type and content, as well as light power density (PD) and irradiation time.…”