# Fabrication of Self-Healable Magnetic Nanocomposites via Diels - Alder Click Chemistry
## 2 Materials and Methods
### Methods
#### 2.2.4 Characterization Methods  
\({}^{1}\)H NMR analysis of the PCLF copolymer was conducted by using a 400 MHz Bruker Avance spectrometer at room temperature. CDCl\({}_{3}\) was used as solvent for this measurement. The measurements of the molecular weight and molecular weight distribution of the synthesized PCLF were carried out by using a Viscotek TDA 305 system equipped with a refractive-index detector. THF was used as a mobile phase at an operating temperature of 35 \({}^{\circ}\)C. For the hybrid material system, the investigations of nanomorphologies were performed using a Hitachi H-7650 transmission electron microscopy operating at 75 kV with a Gaten model 782 CCD camera. Elemental analyses were performed by using an energy-dispersive X-ray spectroscopy detector (Oxford x-act) attached to a Hitachi TM4000 PLUS scanning electron microscopy. ATR-FTIR measurements were carried out on a Perkin Elmer Spectrum One spectrometer. Wide-angle X-ray scattering (WAXS) experiments of the hybrid samples were conducted at beamline 13A1 of the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. The wavelength of the incident beam was set as 1.033 A for the WAXS analyses. Additionally, rectangular shape samples (5 mm \(\times\) 5 mm \(\times\) 1 mm) were used for the X-ray measurements, and the detection time was set as 30 min for each sample. Thermogravimetric analyses (TGA) of these hybrid samples were performed by using a Hitachi STA7200 instrument. These measurements were carried out by heating the samples from 50 \({}^{\circ}\)C to 600 \({}^{\circ}\)C at a heating rate of 10 \({}^{\circ}\)C/min under N\({}_{2}\) atmosphere. A Hitachi DSC7000X differential scanning calorimetry was used to analyze the thermal properties of the hybrid materials. These samples were measured through a heating process from \(-\)30 \({}^{\circ}\)C to 200 \({}^{\circ}\)C at a rate of 5 \({}^{\circ}\)C/min. The magnetic properties of the hybrid samples were studied using a Microsense 1660 Torque Vibratory Sample Magnetometer (VSM) system. These measurements were performed at room temperature under applied field in the range from \(-\)10,000 to 10,000 Oe, and started from \(-\)10,000 Oe with different step sizes (\(-\)10,000 \(\sim-\)2000 Oe: scan step = 1000 Oe; \(-\)2000 \(\sim-\)200 Oe: scan step = 200 Oe; \(-\)200 \(\sim\) 0 Oe: scan step = 20 Oe). The self-healing ability of the hybrid system was studied by investigating the evolution of a crack healing under a Nikon ECLIPSE LV100N POL polarizing optical microscope equipped with a CCD camera. Rectangular shape samples of crosslinked PCLF/BMI/IONPs-MWCNTs hybrid (5 mm \(\times\) 5 mm \(\times\) 1 mm) were cut by using a razor blade to form a crack on the surface of the samples. The cracked samples were heated in-line using a Linkam THMS600 hot stage to a specified temperature. As the setting temperature was achieved, the measured samples were isothermally heated for 5 min before investigation. Additionally, the crack evolution before and after the self-healing process was also investigated by using a Hitachi FlexSEM 1000 scanning electron microscopy.