Three-dimensional porous crystalline polyimide covalent organic frameworks (termed PI-COFs) have been synthesized. These PI-COFs feature non- or interpenetrated structures that can be obtained by choosing tetrahedral building units of different sizes. Both PI-COFs show high thermal stability (>450 °C) and surface area (up to 2403 m(2) g(-1)). They also show high loading and good release control for drug delivery applications.

Superhydrophilic poly(ethyleneimine)/poly(sodium-4-styrenesulfonate) (PEI/PSS)-calcium silicate hydrate (CSH) multilayered membranes (PEI/PSS) 2.0 (PEI/PSS-CSH) n on polyacrylonitrile (PAN) substrate were prepared via layer-by-layer (LbL) assembly with in situ precipitation of consecutive Ca 2+integrated multilayered polyelectrolytes and sodium silicate. The surface structure and properties of these multilayered membranes (PEI/PSS) 2.0 (PEI/PSS-CSH) n were characterized by zeta potential, infrared resonance spectra, water contact angles, scanning electron microscopy, and atomic force microscopy, and the separation performances were evaluated by rejection of dyes, such as xylenol orange (XO) and rhodamine B (RB). The long term performance, self-cleaning and antifouling behaviors were investigated by retention of aqueous solutions of both dyes and bovine serum albumin (BSA) aqueous solution. The results indicated that the in situ incorporation of controlled CSH contents into PEI/PSS multilayers greatly improved the hydrophilicity of the multilayered membranes, resulting in the formation of a superhydrophilic (PEI/PSS-CSH) 2.0 membrane with a water contact angle of 2.1 and the highest permeate fluxes of 191.5 and 183.5 L m À2 h À1 MPa À1 accompanied by the rejection of 94.0% and 91.2% for XO and RB aqueous solutions, respectively. When the number of assembled (PEI/ PSS-CSH) n multilayers was higher than 2.0 bilayers, the rejection increased but the flux markedly decreased to XO and RB dyes, showing a characteristic trade-off phenomenon. Moreover, the superhydrophilic (PEI/PSS-CSH) 2.0 membrane possessed a higher antifouling and self-cleaning behavior than the hydrophilic polyelectrolytes (PEI/PSS) 2.0 .

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A new anion conducting covalent organic framework (COF) was prepared by covalently tethering quaternary ammonium (QA) ions onto the pore walls of COF 1,3,5-triformylphloroglucinol-o-tolidine (TpBD-Me) through bromination and quaternization.