# Synthesis, Characterization, and Self-Assembly of a Tetrathiafulvalene (TTF)-Triglycyl Derivative
## 2 Materials and Methods
### Preparation and Characterization of Gel Materials  
Anhydroous solvents used for gelation tests were purchased from commercial suppliers. Gelation tests were carried out in screw-capped glass vials (4 cm length \(\times\) 1 cm diameter) having a specific amount of the TTF derivative **14** and the desired solvent (1 mL). The mixture was heated with a standard heat gun until complete dissolution. Then, the clear solution was allowed to cool down to RT. The material was initially classified as gel if it did not flow by turning the vial upside-down. The viscoelastic nature was further confirmed by rheology of a model system.  
Critical gelation concentration (CGC) corresponds to the minimum gelator concentration required for gelation. The values were obtained by continuously adding aliquots of solvent (0.02-0.1 mL) into vials having the TTF derivative **14** and performing either the heating or cooling until no gelation was observed. The waiting time used to define the state of the material was \(\sim\)12 h. Concentrations above 200 g/L were not tested.  
Thermal _gel_-to-_sol_ transition temperature (\(T_{\mathrm{gel}}\)) values were determined using a calibrated thermblock at 1 \({}^{\circ}\)C/5 min (Figure S1). The temperature at which the bulk gel started to break was defined as \(T_{\mathrm{gel}}\). Due to potential effects of thermal history and hysteresis [75], the apparatus has been previously calibrated with samples measured by differential scanning calorimetry (DSC) [76].  
Rheological measurements were performed with an AR 2000 Advanced rheometer (TA Instruments, New Castle, DE, USA). Conditions: 1000 mm gap, torque = 5 \(\times\) 10\({}^{-4}\) N/m, 25 \({}^{\circ}\)C, plain-plate geometry (20 mm, stainless steel), sample volume = 2 mL. Dynamic strain sweep (DSS) measurements were performed between 0.01 and 100% strain. For dynamic frequency sweep (DFS) measurements, frequency was varied from 0.1 to 10 Hz at 0.1% strain. Finally, dynamic time sweep (DTS) measurements were carried out within the linear regime at 0.1% strain and 1 Hz frequency.  
FT-IR spectra were obtained at RT with a Cary 630 FTIR spectrometer (Agilent Technologies, Santa Clara, CA, USA) equipped with an attenuated total reflection (ATR) accessory (32 scans, spectral resolution = 8 cm\({}^{-1}\)).  
Field emission scanning electron microscopy (FE-SEM) of xerogels was carried out with a Zeiss Merlin, Field Emission Scanning Electron Microscope (accelerating voltage = 10 kV). Xerogels, prepared by freeze-drying the gels, were placed on top of a tin plate and shielded with Pt (40 mA, 30-60 s; film thickness = 5-10 nm). Images were by Servicio General de Apoyo a la Investigacion-SAI (University of Zaragoza).  
Images under polarized light were obtained using a Wild Makroskop M420 optical microscope equipped with a Canon Power shot A640 camera.  
UV-vis spectra were obtained with an Ocean Optics, Flame spectrometer with a DH-2000-BAL light source or on a Varian Cary 50 UV spectrophotometer. Quartz-glass cuvettes of 0.5 cm thickness were used.  
Iodine doping was achieved by exposing the xerogel to I\({}_{2}\) vapor for _circa_ 120 min in a sealed glass beaker with I\({}_{2}\) crystals.