Jis special grade

PHA extraction and purification was carried out according to the method reported in (Brandl et al., 1989 (link)). PHAs were extracted from 428 mg lyophilized cells using about 100 mL of chloroform (JIS Special Grade, Wako Chemicals, Osaka, Japan). The chloroform extracts were filtered and concentrated using a rotary vacuum evaporator (NA-1, AS ONE, Osaka, Japan), and the chloroform-extracted PHAs were purified by precipitation with hexane (JIS Special Grade, Wako Chemicals, Osaka, Japan) of more than 10 times the volume of the solvent. The precipitate was filtered and then air-dried without vacuum as a convenient way overnight at room temperature. The polymer solution was concentrated again using a rotary vacuum evaporator and purified by precipitation with cold methanol (JIS Special Grade, Wako Chemicals, Osaka, Japan) of more than 10 times the volume of the solvent. The purified PHA precipitate was air-dried overnight at room temperature.
The purified PHAs were analyzed by proton nuclear magnetic resonance (¹H NMR; JNM-Excalibur 270; JEOL, Ltd., Tokyo, Japan) to determine their chemical structures and compositions. The measuring frequency was 499.87 MHz. The sample for NMR analysis was dissolved at a concentration of 4 mg/mL in CDCl₃ with 0.05% (v/v) tetramethylsilane (TMS; Wako Pure Chemical Industries Ltd., Osaka, Japan).

SrTiO₃ (100) single-crystal substrates were purchased from SHINKOSHA CO., LTD. Mg powder (212–600 μm, 99.9%, Wako, Osaka, Japan) and MgB₂ powder (99%; Sigma-Aldrich, St. Louis, MO, USA) were purchased to use MgB₂ thin film deposition. Acetonitrile (99.5% (JIS Special grade), FUJIFILM Wako Pure Chemical Industries Ltd., Osaka, Japan), a cation-exchange resin (15JS-HG⋅DRY, Organo Corp., Tokyo, Japan) and formic acid (Kanto Chemical Co., Inc., Tokyo, Japan) were purchased for ion-exchange treatment.
A pulsed laser ablation device (PLFD-221-1R, Freedom Ltd., Kawasaki, Japan) was used for PLD. X-ray diffractometer (Smartlab, Rigaku Corporation, Tokyo, Japan), laser microscope (LEXT OLS5100, Olympus Corporation, Tokyo, Japan), TOF-SIMS 5-100-AD (ION-TOF GmbH, Germany), FT/IR-6100 (JASCO, Co., Ltd., Tokyo, Japan), atomic force microscope (SPM-9700, Shimadzu Corp., Kyoto, Japan) and scanning electron microscope (JEM-2010F, JEOL, Ltd., Tokyo, Japan) were used for characterization of prepared films.

Magnesium diboride powder (MgB₂, 500 mg, 99%; Sigma-Aldrich, St. Louis, MO, USA) and a cation-exchange resin (30 mL, Amberlite IR120B hydrogen form; Organo Corp., Tokyo, Japan) were added to acetonitrile (99.5%, JIS special grade; Wako, Osaka, Japan) at room temperature, followed by stirring at the atmospheric pressure in an N₂ atmosphere. After 3 days of stirring, the remaining MgB₂ and resin were removed from the solution via a membrane filter (Omnipore 0.2 μm; Merck Millipore Ltd, Ireland). The filtrate, which was a yellow dispersion, was dried under a reduced pressure at 313 K, yielding HB sheets in the form of yellow powder.