Fast Triggering of Shape Memory Polymers using an Embedded Carbon Nanotube Sponge Network

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Shape memory polymers (SMPs) are advanced materials with the ability to return to their original shape when stimulated.
• Integrating conductive fillers can enhance SMPs' properties and enable new functionalities like electrical triggering.
• Carbon nanotube sponges (CNTS) offer high surface area and excellent electrical conductivity for composite applications.

Purpose of the Study:

• To develop a novel carbon nanotube sponge/shape memory polymer (CNTS/SMPs) nanocomposite.
• To investigate the effect of CNTS incorporation on the properties of SMPs, particularly thermal and electrical characteristics.
• To evaluate the electrical triggering capability and response time of the developed nanocomposite.

Main Methods:

• Fabrication of CNTS/SMPs nanocomposite via infiltration of SMPs into a 3-D CNTS matrix.
• Characterization of material properties, including glass transition temperature (Tg) and electrical conductivity.
• Evaluation of electrical triggering performance using applied voltage and time measurements.
• Finite element simulations to model thermal behavior and validate experimental findings.

Main Results:

• Complete infiltration of SMPs into the CNTS structure was achieved using capillary forces without damaging the CNTS.
• A low carbon nanotube loading (~0.2 wt%) significantly increased the glass transition temperature of the SMP by ~20°C.
• The uniform distribution of CNTS resulted in high electrical conductivity and effective electricity triggering.
• The CNTS/SMPs nanocomposite demonstrated rapid triggering (within ~10 seconds) at ~10 volts.
• Finite element simulations confirmed experimental results and indicated minimal interface thermal energy loss impact.

Conclusions:

• The developed CNTS/SMPs nanocomposite exhibits enhanced thermal properties and efficient electrical triggering capabilities.
• The strong interaction between CNTS and the SMP matrix is crucial for property enhancement.
• This material shows promise for applications requiring fast-response, electrically activated shape memory effects.