NU 2020-132
INVENTORS Mark C. Hersam* William R. Dichtel* Nathan P. Bradshaw Austin M. Evans
SHORT DESCRIPTION A new method for additive manufacturing of 2D covalent organic framework (COF) thin-films on various substrates using spray-coating
BACKGROUND 2D COFs are crystalline, two-dimensional polymers that have molecularly precise pore sizes. 2D COFs have a wide variety of applications, including use in sensors, electronic components, gas/liquid storage and purification devices, catalysts, etc. However, the inability to scale up the manufacturing of 2D COFs has limited their commercial utility. Previous methods of depositing 2D COFs on substrates have involved direct growth, continuous flow, interfacial polymerization, electrophoretic deposition, and inkjet printing. However, none of these methods allow for deposition of fully synthesized COFs on a wide variety of substrates, scaling up, or patterning of the COFs.
ABSTRACT This invention describes a facile method for the additive manufacturing of 2D COFs. Colloidal inks of fully synthesized 2D COFs are prepared and spray-coated on substrates using commercially available airbrushes. This allows for the direct deposition of fully synthesized 2D COFs on a wide variety of substrates. This method can produce large (>200 cm2) 2D COF thin-films quickly (<5 min), with high resolution (<50 micron) and without the need for post-processing or specialized equipment. Thus, this invention allows for the large-scale additive manufacturing of 2D COF thin-films, which overcomes prior limitations in the field and may enable the commercial production of various 2D COF-containing devices. Traditional organic radicals are not stable in air, and NIR dyes with absorption wavelength longer than 1300 nm is difficult to obtain. Northwestern researchers have developed two new highly positively charged catenanes that display highly stable mono-and diradical states under ambient conditions and with good NIR absorbing ability longer than 1300 nm. Their results demonstrate that “mechanical-bond-induced-stablization” is an efficient way to achieve highly stable mono-and diradicals. The mixed-valence nature of the [2]catenanes endow them interesting redox and optic properties. Two new highly charged [2]catenanes—namely, mHe[2]C•6PF6and mHo[2]C•6PF6—were synthesized. Electrochemical studies indicate that the first two reduction peaks of these two [2]catenanes are significantly positively shifted, a feature which is responsible for their extraordinary stabilities in air. The mixed-valence nature of the mono-and bis-radical states endows them with unique NIR-absorption properties, e.g. NIR absorption bands for the monoradical and bisradical states observed at ~1800 nm and ~1450 nm, respectively.
APPLICATION
ADVANTAGES
PUBLICATION Evans AM, Bradshaw NP, Litchfield B, Strauss MJ, Seckman B, Ryder MR, Castano I, Gilmore C, Gianneschi NC, Mulzer CR, Hersam MC and Dichtel WR (2020) High‐Sensitivity Acoustic Molecular Sensors Based on Large‐Area, Spray‐Coated 2D Covalent Organic Frameworks. Advanced Materials. 32: 2004205.
IP STATUS Provisional and PCT applications have been filed.