# 4D Printing of Origami Structures for Minimally Invasive Surgeries Using Functional Scaffold
## 3 Results and Discussion
### Deformation and Shape Recovery of the PLA Filaments  
The recovery behaviour of the PLA filaments, both the deformed and the recovered, is shown in Tables 1-3. There was an expectation that the results would show decreasing rates of recovery as the intended test angle was increased. This expectation was due to higher forces being applied to achieve the greater angle deformations. This expectation was shown to be incorrect, as shown in Tables 1 and 2. In fact, the results of the experiment showed no correlation between changes in the intended test angle and the percentage recovered. The lack of correlation would have significant implications for future scaffold designs. The result showed that PLA polymer recover around 61.5% with SD of 4.3% regardless of the bending angle. \begin{table}
\begin{tabular}{|c|c|c|c|c|c|} \hline  & **Repeat 1** & **Repeat 2** & **Repeat 3** & **Repeat 4** & **Repeat 5** \\ \hline
30\({}^{\circ}\) & & & & & \\ \hline
60\({}^{\circ}\) & & & & & \\ \hline
90\({}^{\circ}\) & & & & & \\ \hline
120\({}^{\circ}\) & & & & & \\ \hline
150\({}^{\circ}\) & & & & & \\ \hline
180\({}^{\circ}\) & & & & & \\ \hline \end{tabular}
\end{table} 
Table 1: Deformed PLA test samples. Figure 3: Dynamic mechanical thermal properties of the PLA filaments. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Intended Test Angle**} & \(\mathbf{30^{\circ}}\) & \(\mathbf{60^{\circ}}\) & \(\mathbf{90^{\circ}}\) & \(\mathbf{120^{\circ}}\) & \(\mathbf{150^{\circ}}\) & \(\mathbf{180^{\circ}}\) \\ \hline \multirow{4}{*}{**Repeat 1**} & Actual test angle & \(30^{\circ}\) & \(53^{\circ}\) & \(81^{\circ}\) & \(110^{\circ}\) & \(133^{\circ}\) & \(160^{\circ}\) \\ \cline{2-7}  & Angle post-recovery & 12 & 22 & 28 & 42 & 50 & 58 \\ \cline{2-7}  & Percentage recovered & 60.0\% & 58.5\% & 65.4\% & 61.8\% & 62.4\% & 63.8\% \\ \hline \multirow{4}{*}{**Repeat 2**} & Actual test angle & \(31^{\circ}\) & \(50^{\circ}\) & \(80^{\circ}\) & \(112^{\circ}\) & \(131^{\circ}\) & \(158^{\circ}\) \\ \cline{2-7}  & Angle post-recovery & 15 & 22 & 27 & 32 & 50 & 66 \\ \cline{2-7}  & Percentage recovered & 51.6\% & 56\% & 66.3\% & 71.4\% & 61.8\% & 58.2\% \\ \hline \multirow{4}{*}{**Repeat 3**} & Actual test angle & \(23^{\circ}\) & \(52^{\circ}\) & \(77^{\circ}\) & \(108^{\circ}\) & \(136^{\circ}\) & \(157^{\circ}\) \\ \cline{2-7}  & Angle post-recovery & 8 & 24 & 31 & 37 & 50 & 61 \\ \cline{2-7}  & Percentage recovered & 65.2\% & 53.8\% & 59.7\% & 65.7\% & 63.2\% & 61.1\% \\ \hline \multirow{4}{*}{**Repeat 4**} & Actual test angle & \(30^{\circ}\) & \(49^{\circ}\) & \(79^{\circ}\) & \(108^{\circ}\) & \(137^{\circ}\) & \(156^{\circ}\) \\ \cline{2-7}  & Angle post-recovery & 14 & 18 & 28 & 40 & 53 & 60 \\ \cline{2-7}  & Percentage recovered & 53.3\% & 63.3\% & 64.6\% & 63.0\% & 61.3\% & 61.5\% \\ \hline \multirow{4}{*}{**Repeat 5**} & Actual test angle & \(34^{\circ}\) & \(54^{\circ}\) & \(82^{\circ}\) & \(106^{\circ}\) & \(142^{\circ}\) & \(158^{\circ}\) \\ \cline{2-7}  & Angle post-recovery & 13 & 23 & 29 & 41 & 48 & 60 \\ \cline{2-7}  & Percentage recovered & 61.8\% & 57.4\% & 64.6\% & 61.3\% & 66.2\% & 62.0\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Recovered PLA test samples.