The primary shape (stress-free)of the sample was set to be a linear rectangular bar. The originalshape was easily deformed into spiral shape (a temporary shape) at70 C, which was prepared using a Teflon rod. By subsequentcooling at room temperature, the temporary shape was fixed. Uponreheating above Tm, the deformed shapewas restored to its originalshape. These deformation and recovery processes were repeatedlypracticable.