Supporting Information Polymer Inorganic Composites with Dynamic Covalent Mechanochromophore Takahiro Kosuge,, Keiichi Imato, Raita Goseki,, and Hideyuki tsuka*,, Department of rganic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 okayama, Meguro-ku, Tokyo 152-8550, Japan Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 okayama, Meguro-ku, Tokyo 152-8550, Japan E-mail: otsuka@polymer.titech.ac.jp 1
MATERIALS AND METHDS General Procedures. Dichloromethane (dehydrated, Kanto Chemical Co., Inc.), 3- isocyanatepropyltrimethoxysilane (IPTMS) (95 %, Gelest, Inc.), di-n-butyltin dilaurate (DBTDL) (>95.0%, Tokyo Chemical Industry Co., Ltd.), di-n-butyltin bis(acetylacetonate) (Sn(acac)Bu 2 ) (95%, Alfa Aesar) and X-map (Si-PBA) (M n = 24 000; M w /M n = 1.3, donated by Kaneka Co.) were used as received without further purification. DABBF-diol and DABBF-tetraol were synthesized according to our previous reports. [1] Gel permeation chromatograph (GPC) measurements were carried out at 40 C on TSH HLC-8320 GPC system equipped with a guard column (TSH TSK guard column Super H-L), three columns (TSH TSK gel SuperH 6000, 4000, and 2500), a differential refractive index detector, and a UV-vis detector. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 0.6 ml/min. Polystyrene (PS) standards (M n = 4 430 3 242 000; M w /M n = 1.03 1.08) were used to calibrate the GPC system. FT-IR spectroscopic measurement was recorded on a JASC FT/IR-4100 with a NaCl plate. 1 H-NMR spectroscopic measurements were carried out at 25 C using Bruker DPX300 (300 MHz) with tetramethylsilane (TMS) as internal standard in chloroform-d (CDCl 3 ). Thermogravimetric analysis (TGA) was performed in the temperature range from r.t. to 600 C at a heating rate of 10 C /min, in nitrogen environment, flow rate 50 ml/min using a SIMAZU DTG-60. Synthesis of DABBF-bis(trimethoxysilane). In a test tube, a DABBF-diol (2.00 g, 2.53 mmol) and IPTMS (1.21 ml, 6.33 mmol) were dissolved in dry dichloromethane (1.00 ml), followed by adding 0.500 ml of di-n-butyltin dilaurate (76.2 ml) solution in dichloromethane (1.00 ml) to the mixture at 0 C under a nitrogen atmosphere. The reaction mixture was allowed to stand at 35 C for 2 hours. The reaction was evaluated by GPC, FT-IR, and 1 H NMR measurements. 2
Synthesis of Si-DABBF 1. A solution (0.500 ml) of di-n-butyltin bis(acetylacetonate) (380 ml, 1.08 mmol) in dichloromethane (1.00 ml) was added to the above-mentioned solution of DABBF-bis(trimethoxysilane). Then, the mixture was poured into a PFA petri dish (f76 mm) and cured for 1 week in air at r.t. Synthesis of DABBF-tetrakis(trimethoxysilane) and Si-DABBF 2. DABBF-tetraol (1.00 g, 1.22 mmol) and IPTMS (1.16 ml, 6.10 mmol) were dissolved in dry dichloromethane (0.750 ml), followed by adding 0.25 ml of di-n-butyltin dilaurate (73.4 ml) solution in dichloromethane (0.500 ml) to the mixture at 0 C under a nitrogen atmosphere. The reaction mixture was allowed to stand at 35 C for 2 hours. The reaction was evaluated by similar analysis to DABBF-bis(trimethoxysilane). After the reaction, a solution (0.500 ml) of di-nbutyltin bis(acetylacetonate) (380 ml, 1.08 mmol) in dichloromethane (1.00 ml) was added to the reacted solution. Then, the mixture was poured into a PFA petri dish (f50 mm) and cured for 1 week in air at r.t. Synthesis of elastomers with DABBF-bis(trimethoxysilane) and Si-PBA. In a typical preparation of Si-PBA/DABBF-35 for tensile tests, a solution of DABBFbis(trimethoxysilane) prepared from 1.00 g of DABBF-diol was added to a solution of Si- PBA (3.00 g) in dichloromethane (3.00 ml), and di-n-butyltin bis(acetylacetonate) (380 ml, 1.08 mmol) was added to the mixture. Then the mixture was poured into a PFA petri dish (f100 mm), cured for 2 weeks in air at r.t., and dried under reduced pressure. The samples for tensile-epr measurements were prepared by a similar process using PTFE sheet-pasted glass mold (150 mm x 50 mm) instead of PFA petri dish. Tensile tests. The elastic film samples Si-PBA/DABBF-0, 5, 16, 25, and 35 were punched out dumbbell shaped specimens (JIS K 6251-7, 12 mm x 2 mm x 0.2-0.4 mm) and rectangle shaped specimens (3 mm x 125-136 mm x 0.2-0.3 mm). The specimens were stretched in air at r.t. by using a Shimadzu EZ graph equipped with a 50 N load cell at a crosshead speed of 3
100 mm min -1. The measurements were performed using five test pieces for each sample; three of them were chosen. Average values were determined from these three tested samples. EPR measurements of ground samples. The samples (200 mg) were ground 10 minutes in air at r.t. using Asone Automatic Mill DAM-100SA STM-D at a speed of 100 rpm, with a milling direction switching ratio of 0.05 s -1 and a pestle height of 4.00 cm. EPR measurements were carried out on a JEL JES-X320 X-band EPR spectrometer. The ground samples were contained in 5 mm glass capillaries, and the capillaries were sealed after being degassed. Spectra were measured using microwave power of 0.1 mw and a field modulation of 0.1 mt with a time constant of 0.03 s and a sweep rate of 0.25 mt s -1. The concentration of the radicals formed from cleaved DABBF was determined by comparing the area of the observed integral spectrum with that of TEMPL in benzene under the same experimental conditions. The g value was calculated according to the following equation: g = hν / βh where h is the Plank constant, ν is the microwave frequency, β is the Bohr magneton, and H is the magnetic field. Tensile-EPR measurements of film samples. EPR measurements of Si-PBA/DABBF-16 and -35 films (3 mm x 125-136 mm x 0.2-0.3 mm) under tensile deformation were carried out on a JEL JES-X320 EPR X-band spectrometer equipped with a BALDWIN tensile tester in air at r.t. The films were assessed at a strain of every 10%. The stretching speed was 100 mm min -1. Spectra were measured using microwave power of 1 mw and a field modulation of 0.2 mt with a time constant of 0.03 s and a sweep rate of 1.5 mt s -1. The concentration of the radicals from cleaved DABBF was determined by comparing the area of the observed integral spectrum with that of TEMPL in benzene under the same experimental condition; the Mn 2+ signal was used as an auxiliary standard. The g value was calculated the above-described equation. The measurements were performed using five test pieces. 4
Temperature-variable-EPR measurements. EPR measurements were carried out on a JEL JES-X320 X-band EPR spectrometer equipped with a JEL DVT temperature controller. The measured samples were cut to small pieces and filled to 5 mm glass capillaries, and the capillaries were sealed after being degassed. Spectra were measured using microwave power of 0.2 mw and a field modulation of 0.2 mt with a time constant of 0.03 s and a sweep rate of 1.5 mt s -1. The concentration of the radicals formed from cleaved DABBF was determined by comparing the area of the observed integral spectrum with that of TEMPL in benzene under the same experimental condition; the Mn 2+ signal was used as an auxiliary standard. The g value was calculated the above-described equation. 5
(Me)3 Si H N a b d e f c H a g' h b d e f i' c k' N H j' l' m' n Si(Me) 3 g i h j H CN k l m n Si(Me) 3 Figure S1. 1 H-NMR spectra of DABBF-diol (blue), IPTMS (red), and DABBFbis(trimethoxysilane) (green). 6
2 h! 0 h! 12.5! 13! 13.5! 14! 14.5! Retention time / min Figure S2. GPC curves of the reaction solution of DABBF-bis(trimethoxysilane) before adding DBTDL (blue) and after 2 h reaction (red). 2h# 0#h# Absorbance 4000! 3500! 3000! 2500! 2000! 1500! 1000! 500! Wavenumber / cm -1 Figure S3. FT-IR spectra of the reaction solution of DABBF-bis(trialkoxysilane) before adding DBTDL (blue) and after 2 h reaction (red). 7
(Me)3 Si Si(Me) 3 NH H N a b d e c f g' h' i' j 2 ' HN k' N H j 1' k' l' m' n Si(Me) 3 H H a b d e l' m' n Si(Me) 3 c f g h i H j 1 H j 2 k CN l m n Si(Me) 3 Figure S4. 1 H-NMR spectra of DABBF-tetraol (blue), IPTMS (red) and reaction solution of DABBF- tetrakis(trimethoxysilane) (green). 8
2 h! 0 h! 11! 11.5! 12! 12.5! 13! 13.5! 14! 14.5! Retention time / min Figure S5. GPC curves of the reaction solution of DABBF-tetrakis(trimethoxysilane) before adding DBTDL (blue) and after 2 h reaction (red). 2h# 0#h# Absorbance 4000! 3500! 3000! 2500! 2000! 1500! 1000! 500! Wavenumber / cm -1 Figure S6. FT-IR spectra of the reaction solution of DABBF-tetrakis(trialkoxysilane) before adding DBTDL (blue) and after reacting 2 hours (red). 9
100! Weight / %! 80! 60! 40! 20! Si-DABBF 2! Si-DABBF 1! 65! 35! 25! 16! 5! 0! 0! 0! 100! 200! 300! 400! 500! 600! Temperature / Figure S7. TGA curves of Si-DABBF 1, Si-DABBF 2, Si-PBA/DABBF-0, -5, -16, -25, -35 and -65. 10
(a) (b) (c) (d) Figure S8. Plots of (a) Young's modulus, (b) fracture stress, (c) fracture strain, and (d) fracture energy versus weight content of DABBF alkoxysilane. Figure S9. Schematic illustrations of stretching activation mechanisms for DABBF mechanophores in (a) low DABBF alkoxysilane content Si-PBA/DABBF and (b) high DABBF alkoxysilane content Si-PBA/DABBF. 11
Table S1. Weight Ratios of Si-PBA and DABBF for Synthesis of Cross-linked Polymers (Si-PBA/DABBF-0, -5, -16, -25, -35, -65) Si-PBA/DABBF-x x = 0 5 16 25 35 65 Si-PBA content (wt%) 100 95 84 75 65 35 DABBF-alkoxysilane content (wt%) 0 5 16 25 35 65 Table S2. Mechanical Characteristics of Si-PBA/DABBF-0, -5, -16, -25, and -35 Films Sample Young's Modulus (KPa) Fracture Stress (MPa) Fracture Strain (%) Fracture Energy (MJm -3 ) Si-PBA /DABBF - 0 2.86 ± 0.148 0.438 ± 0.0379 270 ± 13.8 0.0006413 ± 0.0000718 Si-PBA /DABBF - 5 2.87 ± 0.235 0.596 ± 0.0285 296 ± 16.6 0.000918 ± 0.0000738 Si-PBA /DABBF - 16 1.04 ± 0.0533 1.09 ± 0.164 509 ± 43.3 0.000641 ± 0.000511 Si-PBA /DABBF - 25 4.27 ± 0.250 5.12 ± 0.170 550 ± 18.7 0.0116 ± 0.000467 Si-PBA /DABBF - 35 28.6 ± 0.0452 6.56 ± 0.379 397 ± 16.6 0.0136 ± 0.00124 [1] a) K. Imato, M. Nishihara, T. Kanehara, Y. Amamoto, A. Takahara, H. tsuka, Angew. Chem. Int. Ed. 2012, 51, 1138-1142; b) K. Imato, A. Irie, T. Kosuge, T. hishi, M. Nishihara, A. Takahara, H. tsuka, Angew. Chem. Int. Ed. 2015, 54, 6168-6172. 12