Formamide fa

Sodium hydroxide (NaOH) was purchased from Junsei Chemical Co. (Tokyo, Japan). Octafluorocyclobutane (C₄F₈) gas was obtained from Union Gas (Yongin, South Korea). Chemicals, including dodecyltrimethoxysilane (DTMS), methylene iodide (MI), and formamide (FA), were purchased from Sigma Aldrich (St. Louis, MO, USA). Three different polymeric substrates, cellulose (Cel), polypropylene (PP), and polyethylene terephthalate (PET), were used for surface wetting analysis. Those polymers have different surface energy profiles and are commonly used as nonwoven materials for various applications. Cellulose and PET films were purchased from Goodfellow (Huntingdon, UK). PP films were prepared using PP resin obtained from SK Global Chemical Co., Ltd. (Seoul, South Korea). Cellulose and PET nonwovens were obtained from Korea Institute of Industrial Technology (KITECH, Cheonan, South Korea). The specifications of films and nonwovens used in this study are shown in Table 1.

Titanium (IV) butoxide (TTB, 97%, Sigma-Aldrich, St. Louis, MO, USA), glacial acetic acid (HAc, 99%, Sigma-Aldrich), Pluronic F-127 (F-127, Sigma-Aldrich), absolute ethanol (EtOH, 99.8%, Fisher Scientific, Hampton, NH, USA), formamide (FA, 99.5%, Sigma-Aldrich), urea (99%, Merck, Kenilworth, NJ, USA), and deionized water were used in the present work. All reactants were used as received, without further purification.

All chemicals and solvents for synthesis were used without further purification and purchased from commercial sources.
The solvents, methanol (MeOH; J.T. Baker, HPLC grade), acetonitrile (MeCN; Sigma-Aldrich, St. Louis, MO, USA, HPLC grade), N,N-dimethylformamide (DMF; Sigma−Aldrich, HPLC grade), mQ water (H₂O), formamide (FA; Sigma-Aldrich, spectroscopic grade), and CDCl₃ (euriso-top, +0,03% TMS, 99,80% D) were used without further purification. The salts used for the investigation of calixarene complexation were LiClO₄ (Sigma Aldrich, 99.99%), NaClO₄ (Sigma Aldrich, ≥98%), KClO₄ (Fluka, Buchs, Switzerland, ≥99,0 %), RbCl (Sigma-Aldrich, 99,8%), RbI (Sigma-Aldrich, 99,9 %), RbNO₃ (Sigma-Aldrich, 99,7 %), CsCl (Sigma-Aldrich, 99,9%), CsCI (Sigma-Aldrich, 99,9%), CsNO₃ (Sigma-Aldrich, 99,5%), and Cs[B(C₆H₅)₄] (Sigma-Aldrich, 98%). Due to the inertness of perchlorate and tetraphenylborate anions regarding ion association, alkali salts with these anions were used in the cases when they were soluble enough.