@article {48417,
	title = {Dual nanomechanics in anisotropic porous covalent organic framework janus-type thin films},
	journal = {Journal of the American Chemical Society},
	volume = {144},
	year = {2022},
	month = {JAN},
	pages = {400-409},
	type = {Article},
	abstract = {<p>
	Empowered by crystalline ordered structures and homogeneous fabrication techniques, covalent organic frameworks (COFs) have been realized with uniform morphologies and isotropic properties. However, such homogeneity often hinders various surface-dependent properties observed in asymmetric nanostructures. The challenge remains to induce heterogeneity in COFs by creating an asymmetric superstructure such as a Janus thin film. In this regard, we propose a versatile yet straightforward interfacial layer-grafting strategy to fabricate free-standing Janus-type COF-graphene thin films. Herein, two-dimensional graphene sheets were utilized as the suitable grafter due to the possibility of noncovalent interactions between the layers. The versatility of the approach was demonstrated by fabricating two distinct Janus-type films, with the COF surface interwoven with nanofibers and nanospheres. The Janus-type films showcase opposing surface morphologies originating from graphene sheets and COF nanofibers or nanospheres, preserving the porosity (552-600 m(2) g(-1)). The unique surface chemistries of the constituent layers further endow the films with orthogonal mechanical properties, as confirmed by the nanoindentation technique. Interestingly, the graphene sheets favor the Janus-type assembly of COF nanofibers over the nanospheres. This is reflected in the better nanomechanical properties of COFfiber-graphene films (E-gra(phene) = 300-1200 MPa; E-COF( )= 15-60 MPa) compared to the COFsphere-graphene films (E-gra(phe)ne = 11-14 MPa; E-CO(F )= 2-5 MPa). These results indicate a direct relationship between the mechanical properties and homo/heterogeneity of Janus-type COF films.</p>
},
	issn = {0002-7863},
	doi = {10.1021/jacs.1c10263},
	author = {Mohata, Shibani and Dey, Kaushik and Bhunia, Surojit and Thomas, Neethu and Gowd, E. Bhoje and Ajithkumar, Thalasseril G. and Reddy, C. Malla and Banerjee, Rahul}
}
@article {48416,
	title = {Viscoelastic covalent organic nanotube fabric via macroscopic entanglement},
	journal = {Journal of the American Chemical Society},
	volume = {144},
	year = {2022},
	month = {SEP },
	pages = {16052-16059},
	type = {Article},
	abstract = {<p>
	Covalent organic nanotubes (CONTs) are one-dimensional porous frameworks constructed from organic building blocks via dynamic covalent chemistry. CONTs are synthesized as insoluble powder that restricts their potential applications. The judicious selection of 2,2{\textquoteright}-bipyridine-5,5{\textquoteright}-dicarbaldehyde and tetraaminotriptycene as building blocks for TAT-BPy CONTs has led to constructing flexible yet robust and self-standing fabric up to 3 mu m thickness. The TAT-BPy CONTs and TAT-BPy CONT fabric have been characterized by solid-state one-dimensional (1D) C-13 CP-MAS, two-dimensional (2D) C-13-H-1 correlation NMR, 2D H-1-H-1 DQ-SQ NMR, and 2D N-14-H-1 correlation NMR spectroscopy. The mechanism of fabric formation has been established by using high-resolution transmission electron microscopy and scanning electron microscopy techniques. The as-synthesized viscoelastic TAT-BPy CONT fabric exhibits high mechanical strength with a reduced modulus (E-r) of 8 (+/- 3) GPa and hardness (H) of 0.6 (+/- 0.3) GPa. Interestingly, the viscoelastic fabric shows time-dependent elastic depth recovery up to 50-70\%.</p>
},
	issn = {0002-7863},
	doi = {10.1021/jacs.2c06133},
	author = {Koner, Kalipada and Das, Susobhan and Mohata, Shibani and Duong, Nghia Tuan and Nishiyama, Yusuke and Kandambeth, Sharath and Karak, Suvendu and Reddy, C. Malla and Banerjee, Rahul}
}
