Patterning is one of the research foundations in the fields of nanofabrication, nanomaterials assembly and bioengineering. Ultrahigh-precision patterning at the molecular scale is extremely desirable for the integration fabrication of high-sensitivity sensors and high-performance optoelectronic devices. Due to the incompatibility of traditional photolithography with organic functional molecules, many high-precision non-lithographic patterning techniques, such as dip-pen nanolithography, nanoimprint lithography, block-copolymer self-assembly, and DNA-Origami lithography have been developed. However, an efficient approach to achieving ultra-precise molecular patterns with simple operation, template-independent precision, controllable molecular assembly, and wide molecular generalization is still challenging.

Bubble-template molecular printing (BTMP) method [IMAGE: QU ZHIYUAN]

Recently, a research team led by Professor Song Yanlin and Professor Qiao Yali from the Institute of Chemistry of the Chinese Academy of Sciences (ICCAS), together with Professor Yan Xuehai from CAS’s Institute of Process Engineering (IPE), and other collaborators, proposed a bubble-template molecular printing concept by introducing an ultrathin liquid film of bubble walls as a soft confinement space, and achieved ultrahigh-precision assembly up to 12 nm corresponding to the critical point towards the Newton black film limit. Using the template of bubble arrays, various molecular assembly morphologies were realized without additional surfactants by controlling the bubble rupture location and confirmed by in-situ visualization based on the aggregation-induced emission property of the model molecules. The researchers also pointed out that the disjoining pressure describing the intermolecular interaction between two liquid-air interfaces could predict the highest precision effectively from the perspective of dynamic evaluation of thin liquid film in the foam system. Furthermore, researchers experimentally and theoretically revealed the molecular assembly mechanism in the bubble wall confinement space, and demonstrated that the molecular symmetry is the key point in stabilization of the evolution of foam film and pursuing ultimate precision molecular patterns. The symmetric molecules exhibit better reconfiguration capacity and smaller pre-aggregates than the asymmetric ones, and are helpful in stabilizing the drainage of foam films and construction of high-precision patterns.

The ultrathin liquid film evolution and molecular assembly mechanism [IMAGE: QU ZHIYUAN]

This work affords a guiding clue to precise construction of molecular-level patterns. Combined with molecular engineering, this method could provide promising opportunities for the fabrication of nano- and molecular-scale devices with unique nanoconfinement and performance enhancement. The study, entitled “Bubble wall confinement-driven molecular assembly towards sub-12 nm and beyond precision patterning” was published in Science Advances 2023, 9, eadf3567.

For more information, please contact:

Professor Song Yanlin

Email: ylsong@iccas.ac.cn

Institute of Chemistry,

Chinese Academy of Sciences

Source: Institute of Chemistry,

Chinese Academy of Sciences