Water-soluble bis(N-acylpiperidone)s with aldehyde-like reactivity are reported to react rapidly with polyvinylamine at room temperature, providing unprecedented clean reaction products. Unlike most amine/ketone reactions that result in arbitrary mixtures of imines, aminals, hemiaminals, or hydrates, in the present study hemiaminals, aminals, or hemiaminal/aminal mixtures are exclusively found. Detailed NMR spectroscopy of solutions, gels, and solids, aided by model reactions, reveals that the hemiaminal/aminal ratio depends on pH, water content, and crosslinking density. Network formation is fully reversible upon changes in pH, with the resulting moduli from rheology spanning almost 3 orders of magnitude. The selfhealing ability of the system is probed by rheology as well, demonstrating maintained material properties of fractured and healed samples. The unusually clean, fast, and reversible chemistry highlights bispiperidones as a class of efficient building blocks with unprecedented possibilities in dynamic covalent chemistry.
The surface modification of textile fibers by coating with nanostructured organic–inorganic hybrid materials is presented. The hydrophobic, solvent resistant and mechanically robust coatings were produced by combining the twin monomer 2,2′‐spirobi[benzo‐4H‐1,3,2‐dioxasiline] (TM) and polyalkoxysiloxanes (silica precursor polymers) in a catalyzed polymerization process. For the application in textile finishing, both aqueous emulsions and ethanolic solutions of mixtures were developed. The precisely adjusted ratio of TM and polyalkoxysiloxanes enabled controlling of the organic and inorganic portions in the hybrid layer. The polymerization process can be advantageously combined with the ring‐opening polymerization of hexamethylcyclotrisiloxane (HMCTS). The resulting ethanolic twin prepolymer solutions and the polyethoxysiloxane emulsions were easy to handle and thus represent a novel and attractive binder for PET surfaces. The coated fabrics were analyzed by means of scanning electron microscopy and X‐ray photoelectron spectroscopy showing hybrid material formation as a homogeneous, sealed surface layer. Improved hydrophobicity as well as resistance to mechanical stress was proven by water droplet‐ and Martindale tests.
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