Anhydrous methanol

Dissolve PLLA (Evonik Industries AG, Germany) particles in chloroform (Beijing Chemical Reagent Company, China) solution and stir fully at room temperature until completely dissolved. Then slowly pour the dissolved PLLA into anhydrous methanol (Beijing Chemical Reagent Company) and use glass rod to stir continuously to collect purified PLLA. After the anhydrous methanol becomes turbid, recover the waste liquid and add clean anhydrous methanol again until the purified PLLA is completely collected. Put the recovered PLLA into an electric blast drying oven (DGG-9240B, Shanghai Senxin Experimental Instrument Co., Ltd, China), dry it at 37°C for 3 days and store it for future use.

The PVDF support membrane with a pore size of 0.1 μm and an average thickness of 100 μm was purchased from Hangzhou Anow Microfiltration Co., Ltd. (Hangzhou, China). Pebax-2533 containing 80 wt % of poly(tetramethylene oxide) (PTMEO) and 20 wt % of nylon 12 (PA12) was provided by Arkema (Paris, France), and its structure is shown in Chart 1a. The N₂ (99.999%) and O₂ (99.999%) were supplied by Beijing Beiwen Gas Factory (Beijing, China). Hydrochloric acid, anhydrous methanol, and ethanol were purchased from Beijing Chemical Works (Beijing, China). o-nitrotoluene, p-anisaldehyde, propionic acid, and acetic acid were supplied by Aladdin (Shanghai, China). Pyrrole and anhydrous cobalt dichloride (CoCl₂) was purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Dimethylformamide (DMF) was provided by Xilong Scientific Co., Ltd. (Guangdong, China). Deionized water was used throughout the study.