【Lecture】From Interpenetrating Polymer Networks to Host-Guest Systems Based on Metal-Organic Frameworks
Dr. Tiesheng Wang
University of Sydney
Interpenetrating polymer network (IPN) describes a subset of polymeric composites with two or more chemically independent polymers interweaving together at microscale, nanoscale or even molecular level. By preparing IPN consisting of several functional polymers we can achieve a multifunctional material with a combinatorial benefit for a given application. As demonstrations, we made an IPN containing an ionic conducting polymer and a rubbery elastomer which can work as both an actuator and a tactile sensor; we also synthesized another IPN with an ionic conducting polymer and an electric conducting polymer which can show enhanced performance as electrode for conducting polymer-based supercapacitor (a.k.a. candy cane-like supercapacitor).
The success in exploring functional IPNs motivates us to investigate the interpenetration between polymers and open-porous metal-organic frameworks. We found that by interpenetrating a conducting polymer with an electrically insulating MOF we can obtain a composite with much higher electrical conductivity than the MOF. Furthermore, the MOF can also be used as a removable template for conducting polymer nanostructures.Interpenetrating the MOF with the polymer paves our way towards incorporating materials as guests inside the MOF’s pores. Loading guestsinside these 1-to-2 nm pores is, however, very challenging.We usedPourbaix diagram of a guest and the relevant information about aMOF host (e.g. chemical stability and pore-opening size) to figure out the boundary conditions for a desired ship-in-a-bottle synthesis (termed as Pourbaix Enabled Guest Synthesis, PEGS).By forming the RuO2@MOF systemwe have developed a highly active and stable catalyst for CO oxidation at low temperatures (< 150°C) which can effectively prevent strong CO adsorption on catalyst surface (i.e.surface passivation).As a paralleled study, we used MOF-guest systems as precursors for carbonization. We achieved carbon-based “nano-diatoms” (morphological analogues to naturally existing diatomaceous species) with multiple levels of hierarchy. We have demonstrated one of the potential applications of this material by utilizing it as an anode for lithium-ion batteries, achieving both high specific capacity and good cycling stability even at high charge/discharge rates.
The talk will also cover our recently progress on designing and synthesizing the electro-/photo-active MOFs and their derivatives in the group.
Venue: Meeting Room 201, Basic Energy Science Building
Date: 15:00 on May, 17, 2019