Tuning Topology and Scaffolding Units in Nanoporous Polymeric Materials for Efficient Iodine Adsorption and Detection

Theprecise control of scaffold elements and topologies of nanoporousmaterials shows great prospects in the application of adsorption andseparation. In this work, two kinds of porous polymers, silsesquioxane-basedporous polymers (PCSs) and triazine-based covalent-organicpolymers (covalent triazine-based frameworks, CTFs), were preparedby the Heck reaction and Suzuki reaction of triazine monomers withoctavinylsilsesquioxane and p-phenylboronic acid,respectively. A series of experimental results showed that the specificsurface areas (S (BET)) and the morphologicalstructures of the target materials can be controlled by regulatingthe building modules. The PCSs are irregular nanoporous aggregateswith S (BET) values of 360 & SIM;560 m(2) g(-1), while the CTFs are regular hollowtubular polymers with S (BET) values of about30 & SIM;70 m(2) g(-1). Different S (BET) values result in different adsorption capabilitiesof iodine in the volatile or solution phase. For volatile iodine,the adsorption capacity of CTFs is up to 2.5 g g(-1), larger than that of PCSs, while in iodine-cyclohexane solution,the adsorption capacity of PCSs is larger than that of CTFs. Due tothe fluorescence quenching caused by charge transfer between the polymersand I-2, two polymers can be used to detect I-2 with good selectivity and sensitivity. In this work, the porosity,fluorescence properties, and adsorption capacity of the target materialswere successfully regulated by adjusting the scaffold units and topologicalstructures of starting materials, thus realizing the sensitive detectionand efficient adsorption of iodine.