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Multi-shape active composites by 3D printing of digital shape memory polymers.

Wu J, Yuan C, Ding Z, Isakov M, Mao Y, Wang T, Dunn ML, Qi HJ - Sci Rep (2016)

Bottom Line: We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design.We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat.With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications.

View Article: PubMed Central - PubMed

Affiliation: The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

ABSTRACT
Recent research using 3D printing to create active structures has added an exciting new dimension to 3D printing technology. After being printed, these active, often composite, materials can change their shape over time; this has been termed as 4D printing. In this paper, we demonstrate the design and manufacture of active composites that can take multiple shapes, depending on the environmental temperature. This is achieved by 3D printing layered composite structures with multiple families of shape memory polymer (SMP) fibers - digital SMPs - with different glass transition temperatures (Tg) to control the transformation of the structure. After a simple single-step thermomechanical programming process, the fiber families can be sequentially activated to bend when the temperature is increased. By tuning the volume fraction of the fibers, bending deformation can be controlled. We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design. We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat. With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications.

No MeSH data available.


Related in: MedlinePlus

Self-assembling and disassembling trestle.(a) The design of the trestle. (b) The cross section of the composites strip. (c) The shape of the structure after programming. (d–g) The deformation behavior of the structure in the recovery process.
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f5: Self-assembling and disassembling trestle.(a) The design of the trestle. (b) The cross section of the composites strip. (c) The shape of the structure after programming. (d–g) The deformation behavior of the structure in the recovery process.

Mentions: We first design a self-assembling and disassembling trestle. Figure 5a shows the design of the trestle, which has 4 identical active composite strips connected at the center. Figure 5b shows the cross-section of the composite strip. Every strip has one fiber with higher Tg (fiber 1) and twelve fibers with lower Tg (fiber 2) and the dimensions of the strip are 55 mm (length) by 6 mm (width) by 2 mm (thickness). The volume fractions of fiber 1 and fiber 2 are 1.2% and 14.4% respectively. The structure is stretched with a strain of 8% at 70 °C then cooled to 0 °C. After releasing at the low temperature, the sample bends slightly with a small curvature, as shown in Fig. 5c. When heated, the strips fold and the trestle stands up from the flat shape as shown in Fig. 5d–f. If we continue heating the sample, the trestle goes back to its flat shape (Fig. 5g). This design can be used as an active supporting trestle controlled by external heating.


Multi-shape active composites by 3D printing of digital shape memory polymers.

Wu J, Yuan C, Ding Z, Isakov M, Mao Y, Wang T, Dunn ML, Qi HJ - Sci Rep (2016)

Self-assembling and disassembling trestle.(a) The design of the trestle. (b) The cross section of the composites strip. (c) The shape of the structure after programming. (d–g) The deformation behavior of the structure in the recovery process.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829848&req=5

f5: Self-assembling and disassembling trestle.(a) The design of the trestle. (b) The cross section of the composites strip. (c) The shape of the structure after programming. (d–g) The deformation behavior of the structure in the recovery process.
Mentions: We first design a self-assembling and disassembling trestle. Figure 5a shows the design of the trestle, which has 4 identical active composite strips connected at the center. Figure 5b shows the cross-section of the composite strip. Every strip has one fiber with higher Tg (fiber 1) and twelve fibers with lower Tg (fiber 2) and the dimensions of the strip are 55 mm (length) by 6 mm (width) by 2 mm (thickness). The volume fractions of fiber 1 and fiber 2 are 1.2% and 14.4% respectively. The structure is stretched with a strain of 8% at 70 °C then cooled to 0 °C. After releasing at the low temperature, the sample bends slightly with a small curvature, as shown in Fig. 5c. When heated, the strips fold and the trestle stands up from the flat shape as shown in Fig. 5d–f. If we continue heating the sample, the trestle goes back to its flat shape (Fig. 5g). This design can be used as an active supporting trestle controlled by external heating.

Bottom Line: We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design.We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat.With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications.

View Article: PubMed Central - PubMed

Affiliation: The George Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

ABSTRACT
Recent research using 3D printing to create active structures has added an exciting new dimension to 3D printing technology. After being printed, these active, often composite, materials can change their shape over time; this has been termed as 4D printing. In this paper, we demonstrate the design and manufacture of active composites that can take multiple shapes, depending on the environmental temperature. This is achieved by 3D printing layered composite structures with multiple families of shape memory polymer (SMP) fibers - digital SMPs - with different glass transition temperatures (Tg) to control the transformation of the structure. After a simple single-step thermomechanical programming process, the fiber families can be sequentially activated to bend when the temperature is increased. By tuning the volume fraction of the fibers, bending deformation can be controlled. We develop a theoretical model to predict the deformation behavior for better understanding the phenomena and aiding the design. We also design and print several flat 2D structures that can be programmed to fold and open themselves when subjected to heat. With the advantages of an easy fabrication process and the controllable multi-shape memory effect, the printed SMP composites have a great potential in 4D printing applications.

No MeSH data available.


Related in: MedlinePlus