Nanoscale Design of Nano-Sized Particles in Shape-Memory Polymer Nanocomposites Driven by Electricity

Abstract

In the last few years, we have witnessed significant progress in developing high performance shape memory polymer (SMP) nanocomposites, in particular, for shape recovery activated by indirect heating in the presence of electricity, magnetism, light, radio frequency, microwave and radiation, etc. In this paper, we critically review recent findings in Joule heating of SMP nanocomposites incorporated with nanosized conductive electromagnetic particles by means of nanoscale control via applying an electro- and/or magnetic field. A few different nanoscale design principles to form one-/two-/three- dimensional conductive networks are discussed.

Keywords: nanocomposites; nanoscale design; shape-memory polymers; smart materials.

Figure 1

An initial diagram showing the mechanism of actuation via electrically resistive Joule heating of shape-memory polymer (SMP) nanocomposite.

Figure 2

Typical scanning electron microscopy (SEM) images prior to (left column) and after (right column) five stretching-recovery cycles of the Ni chains in three SMP nanocomposites with a different volume fraction of Ni powder: (a) 5%; (b) 10%; (c) 20%. Reproduced with permission from [43]. Copyright 2008 American Institute of Physics.

Figure 3

Snapshot of shape recovery process (and temperature distribution). Sample A: SMP/CB; Sample B: SMP/CB/CNT (random); Sample C: SMP/CB/CNT (chained). Right inset: sample dimension and experimental setup for Sample C. Reproduced with permission from [46].Copyright 2011 American Institute of Physics.

Figure 4

Snapshot of the shape recovery process in an SMP nanocomposite integrated with 1.2 g of CNT nanopaper. Reproduced with permission from [49]. Copyright 2012 Wiley-Vch Verlag Gmbh & Co.

Figure 5

Schematic illustration of vertically aligned nickel nanostrands to help resistive heating power to transfer from the nanopaper to the underlying SMP. Reproduced with permission from [41]. Copyright 2011 RSC Publishing.

Figure 6

SEM image of the orientation of the nickel nanostrands observed via the thickness of the SMP nanocomposite. Reproduced with permission from [41]. Copyright 2011 RSC Publishing.

Figure 7

(a) Recovery profiles of the SMP composites with aligned and randomly dispersed 8 wt % of magnetic CNTs under 12 V and 36 V voltages, respectively; (b) induction and recovery times of the SMP composites for the two voltages studied. Reproduced with permission from [54].Copyright 2011 American Institute of Physics.