P phenylenediamine pa 1

P-phenylenediamine (Pa-1) was purchased from Sigma, 98%; Trialdehyde phloroglucinol (Tp) was purchased from McLean, Shanghai, China, 97%; Acetone was purchased from Chengdu Kelong Chemical Co., Ltd., Chengdu, China, AR. Microcrystalline cellulose (MCC) was purchased from Sinopharm Chemical Reagent Co., Ltd. Shanghai, China, column chromatography.
P-toluenesulfonic acid (PTSA) was purchased from Tianjin Damao Chemical Reagent Factory, Tianjin, China, AR; N,N-dimethylformamide (DMF) was purchased from Tianjin Zhiyuan Chemical Reagent Co., Ltd., Tianjin, China, AR; Sulfuric acid (H₂SO₄) was purchased from Ningbo Xinzhi Biotechnology, Ningbo, China, analytically pure; sodium periodate (NaIO₄) was purchased from Aladdin reagent, Shanghai, China, AR; Ethylene glycol was purchased from Thermo Fisher Scientific, Waltham, MA, USA, AR. All reagents and solvents are commercially available and used without further purification.
Dialysis bag MD77 was purchased from United Carbon, MWCO 3500. The portable grinder was purchased from Shanghai Wanbo Bio, Shanghai, China, Mini-2-5.

All chemicals and materials
were used as received without further purification: p-phenylenediamine (Pa-1) (>99%, Sigma), benzidine (BD) (98%, Sigma),
1,3,5-triformylphloroglucinol (Tp) (>96%, Ark), 1,3,5-triformylbenzene
(TB) (96%, Acros), acetic acid (AR, 36%, Roth), α-cyclodextrin
(α-CD, ≥98%, Sigma), 3-aminopropyltriethoxysilane (APTES,
99%, Sigma), epichlorohydrin (ECH, ≥99%, TCI), ethanol (>99%,
Acros), sodium hydroxide (NaOH, ≥98%, Sigma), hydrochloric
acid (HCl, 36%, Sigma), polyethylene glycols with various molecular
weights (PEG, 200, 400, 600, 800, 1000, 2000, 4000 Da, Macklin). Sodium
chloride (NaCl, AR, 99.5%), sodium sulfate (Na₂SO₄, AR, 99%), sodium carbonate (Na₂CO₃, AR, 99%),
and gadolinium chloride (GdCl₃, AR, 99%) were provided
by Sinopharm Chemical, China. Dyes including chrome black T, methyl
blue, acid fuchsin, congo red, rose bengal, and methylene blue (MEB)
were supplied by Shanghai Macklin Biochemical Technology, China. Porous
asymmetric α-Al₂O₃ disks (with a 70 nm
pore-top layer, 18 mm in diameter and 1 mm in thickness) as substrates
were purchased from Fraunhofer IKTS, Germany.