*2.1. Materials*

Cotton microcrystalline cellulose (MCC) was purchased from Huzhou City Linghu Xinwang Chemical Co., Ltd. (Huzhou, China), (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTA) was obtained from Chengdu Aikeda Chemical Reagent Co., Ltd. (Chengdu, China), and starch was purchased from Hangzhou Starpro Co., Ltd. (Hangzhou, China).
