Superior thermoelasticity and shape-memory nanopores in a porous supramolecular organic framework

Abstract

Flexible porous materials generally switch their structures in response to guest removal or incorporation. However, the design of porous materials with empty shape-switchable pores remains a formidable challenge. Here, we demonstrate that the structural transition between an empty orthorhombic phase and an empty tetragonal phase in a flexible porous dodecatuple intercatenated supramolecular organic framework can be controlled cooperatively through guest incorporation and thermal treatment, thus inducing empty shape-memory nanopores. Moreover, the empty orthorhombic phase was observed to exhibit superior thermoelasticity, and the molecular-scale structural mobility could be transmitted to a macroscopic crystal shape change. The driving force of the shape-memory behaviour was elucidated in terms of potential energy. These two interconvertible empty phases with different pore shapes, that is, the orthorhombic phase with rectangular pores and the tetragonal phase with square pores, completely reject or weakly adsorb N2 at 77 K, respectively.

Self-assembly as a key player for materials nanoarchitectonics

“…While it is widely appreciated that nanotechnology plays a central role in materials developments involving nanoscale structures, nanotechnology also provides substantial benefits in the development of nanoscale observation and fabrication techniques including deepening our understanding of novel phenomena on the nanoscale and their guiding physical principles [40][41][42][43]. The construction of functional materials from nanoscale units requires essential contributions from non-nanotechnology fields such as supramolecular chemistry with self-assembly/selforganization [44][45][46][47], materials fabrications [48][49][50], and biotechnology [51][52][53][54][55]. Therefore, materials preparation from nanometric units in the nanoscale regime should to be conducted under a novel concept involving the agglomeration of nanotechnology concepts with the above-mentioned diverse research disciplines.…”

Intelligent Nanoarchitectonics for Self‐Assembling Systems

“…They also accomplished shape‐memory switching of assembled nanopores, using a supramolecular organic framework composed of biphenyl‐3,30,5,50‐ tetra carboxylic acid and 1,2‐ bis (4‐pyridyl)ethane . This porous dodecatuple intercatenated framework is formed with rather weak interaction, hydrogen bonding, and is not strong enough to maintain permanently fixed pore structures.…”

Continuous dependence on boundary and Soret coefficients in double diffusive bidispersive convection

“…A double porosity material is one that exhibits usual macro pores, but additionally contains a system of micro pores due to cracks or fissures in the porous skeleton. Such theories have applications to many important areas such as chemical engineering, Enterría et al, 1 Huang et al, 2 Ly et al, 3 ; in landslides, Borja et al, 4 Scotto di Santolo and Evangelista, 5 ; in self ignition of stockpiled coal, Hooman & Maas, 6 ; in land drainage and ensuring stormwater runoff does not pollute, Haws et al, 7 Jensen et al, 8 ; in ensuring clean drinking water from an aquifer, Ghasemizadeh et al, 9 Fretwell et al, 10 ; and there are many others.…”