Dynamic Flow-Assisted Nanoarchitectonics

Abstract

The solution to societal problems such as energy, environmental, and biomedical issues lies in the development of functional material systems with the capacity to address these problems. In the course of human development, we are entering a new era in which nanostructure control is considered in the major development of functional materials. The new concept of nanoarchitectonics is particularly significant in this regard, as it comprehensively promotes further development of nanotechnology and its fusion with materials chemistry. The integration of nanoscale phenomena and macroscopic actions is imperative for practical production of functional materials with nanoscale structural precision. This review focuses on dynamic flow-assisted nanoarchitectonics, wherein we explore the organization and control of functional structures by external mechanical stimuli, predominantly fluid flow. The review then proceeds to select some examples and divide them into categories for the purpose of discussion: structural organization by (i) natural flow, (ii) flow or stress created with artificial equipment or devices (forced flow), and (iii) flow at a specific field, namely interfaces, that is, layer-by-layer (LbL) assembly and the LB method. The final perspective section discusses the future research directions and requirements for dynamic flow-assisted nanoarchitectonics. The meaningful and effective use of nanotechnology and nanoarchitectonics in materials science is set to be a major area of focus in the future, and dynamic flow-assisted nanoarchitectonics is poised to play a significant role in achieving this objective.

Keywords: Langmuir−Blodgett method; device; interface; layer-by-layer assembly; nanoarchitectonics; natural flow; organic semiconductor.

Figure 1

Outline of this review article for flow-assisted nanoarchitectonics mainly including (i) structural organization by natural flow, (ii) structural organization by artificial flow or stress created by equipment or devices, and (iii) structural organization by flow at interfaces (LB method and LbL assembly).

Figure 2

Approaches to assemble cellulose nanocrystals in a concentric manner as attributed to the circulating flow within the droplets, which results from the synergistic and competitive interaction of the Marangoni flow and the capillary effect during the evaporation. Adapted with permission from ref (125). Copyright 2021 Wiley-VCH.

Figure 3

Scalable fabrication of conductive PEDOT:PSS inks via metastable liquid–liquid contact as a ring-shaped film formed by combination between the coffee ring effect and Marangoni vortices during droplet evaporation. Reprinted with permission from ref (129). Copyright 2023 Wiley-VCH.

Figure 4

Fabrication of robust, free-standing mono- and bilayer films of polystyrene-grafted gold nanorods on solid substrates using flow coating. Adapted with permission from ref (132). Copyright 2021 American Chemical Society.

Figure 5

Formation of structural color materials through synchronizing natural convection and Marangoni flow in pendant drops. Reprinted with permission from ref (136). Copyright 2024 American Chemical Society.

Figure 6

A method to create droplet-to-droplet chemical signaling structures using a combination of surfactants, self-assembly and photochemistry, where myelin-like wire structures were formed using the surfactant triethylene glycol monododecyl ether through photocontrolled Marangoni flow. Reproduced under terms of the CC-BY license from ref (137), 2024 American Chemical Society.

Figure 7

A coagulation process for spinning multiwalled carbon nanotubes from a liquid crystalline ethylene glycol dispersion. Adapted with permission from ref (140). Copyright 2008 Wiley-VCH.

Figure 8

Preparation of tubular budding calcium alginate hydrogels and their inorganic phosphate complexes achieved by the addition of inorganic salts using the flow injection technique, a spinning-type process. Reprinted with permission from ref (142). Copyright 2022 Royal Society of Chemistry.

Figure 9

Mass produce entangled fibrous materials consisting of silk fibers from concentrated solutions under hydrodynamic conditions of turbulent flow. Reproduced under terms of the CC-BY license from ref (145), 2022 Springer-Nature.

Figure 10

A schematic of the continuous fabrication process for developing hierarchical assemblies of anisotropic structures. Reproduced under terms of the CC-BY license from ref (148), 2024 Springer-Nature.

Figure 11

A 3D printing approach by the self-organization of liquid crystalline polymer molecules into highly oriented domains during extrusion of the molten feedstock. Reprinted with permission from ref (152). Copyright 2018 Springer-Nature.

Figure 12

A 3D printing of flow-inspired anisotropic patterns with liquid crystalline polymers, where functional objects with stiffness and curvature gradients can be regulated. Reprinted with permission from ref (153). Copyright 2024 Wiley-VCH.

Figure 13

A schematic diagram of the preparation of aggregation-caused quenching dyes using a continuous flow microreactor. Reproduced under terms of the CC-BY license from ref (157), 2022 Springer-Nature.

Figure 14

Droplet microfluidics to generate highly monodisperse protein nanoparticles by exploiting the properties of rapid and continuous mixing within microdroplets. Reproduced under terms of the CC-BY license from ref (161), 2023 American Chemical Society.

Figure 15

Formation of single microparticles with high drug loading and controlled payload release by controlling the interfacial distribution of the polymer under continuous using a microfluidic platform. Reproduced under terms of the CC-BY license from ref (162), 2023 Wiley-VCH.

Figure 16

A scalable and efficient microfluidic-based sheet alignment process for assembling 2D nanosheets into large-area films with highly ordered vertical alignment. Adapted with permission from ref (166). Copyright 2023 Royal Society of Chemistry.

Figure 17

A strategy to fabricate nanocomposites with highly ordered layered structures using shear flow-induced alignment of 2D nanosheets at an immiscible hydrogel/oil interface. Adapted with permission from ref (170). Copyright 2020 Springer-Nature.

Figure 18

Controlled the orientation of chitosan/silk fibroin layer by layer multilayer thin films layer by layer, where dipping direction can be changed by rotating the substrate during deposition. allowing fiber orientation from one direction to two directions. Adapted with permission from ref (180). Copyright 2010 American Chemical Society.

Figure 19

A method to produce aligned SWNT-polymer composites using LbL assembly method, where the alignment of the SWNTs is controlled upon drying steps after washing off excess SWNTs on the poly(vinyl alcohol) surface. Reprinted with permission from ref (184). Copyright 2005 American Chemical Society.

Figure 20

Controlled the orientation of cellulose nanofibrils in LbL assembly films by spray-assisted orientation where cellulose nanofibrils can be easily oriented by oblique incidence spraying to produce films. Reproduced under terms of the CC-BY license from ref (185), 2016 American Chemical Society.

Figure 21

Composite LbL films of cellulose nanofibrils and polyvinylamine with helical alignment assembled by a directed assembly approach with successfully constructing left-handed and right-handed helices with different pitches and rotations with uniform thickness. Reproduced under terms of the CC-BY license from ref (186), 2024 Wiley-VCH.

Figure 22

A simple brushing method to prepare hydrogen-bonded tannic acid/collagen LbL nanofilms. Adapted with permission from ref (187). Copyright 2022 American Chemical Society.

Figure 23

Shearing of the Langmuir film by a rotating disk for the orientation of surfactant molecules at the air–water interface: conventional LB method (left) and LB method with rotor (right). Reprinted with permission from ref (191). Copyright 1995 American Chemical Society.

Figure 24

Sheering LB method with a single disk system and a double disk system. Adapted with permission from ref (192). Copyright 1998 Elsevier.

Figure 25

Ionic liquid-induced local alignment at the air–water interface and superwetting enhanced alignment induced by subsequent spontaneous transfer. Adapted with permission from ref (193). Copyright 2024 American Chemical Society.

Figure 26

Macroscopic chirality of interracially organized molecular assemblies of achiral porphyrins through the direction of the vortex-like flow generated by compression using the LB technique. Adapted with permission from ref (194). Copyright 2011 Wiley-VCH.

Figure 27

Precise control of the circularly polarized luminescence of aggregates consisting of achiral trans-bis(salicylaldiminato)Pt(II) complexes under vortex flow conditions at the air–water interface. Adapted with permission from ref (195). Copyright 2022 Wiley-VCH.

Figure 28

A bottom-up method to synthesize 2D carbon nanosheets using anisotropic carbon nanoring molecules by creating a vortex flow on the water surface. Adapted with permission from ref (199). Copyright 2018 Wiley-VCH.

Figure 29

Fabrication of aligned fullerene C₆₀ nanowhisker thin films at the air–water interface using vortex LB and usage of them as a scaffold for cell culture. Reprinted with permission from ref (200). Copyright 2015 American Chemical Society.

Figure 30

Precise control of hMSC adhesion and differentiation using highly aligned fullerene nanowhisker nanopatterned scaffolds on a solid substrate using the LB technique. Reproduced under terms of the CC-BY license from ref (204), 2020 American Chemical Society.

Figure 31

A dynamic interfacial process for combination between proton-coupled electron transfer and doping phenomenon of polymer–organic semiconductor interfaces. Reprinted with permission from ref (212). Copyright 2023 Springer-Nature.

Figure 32

Brushing and printing orientation controls of organic semiconductor films: (A) Chinese brush coating process; (B) brush printing process; (C) capillary pen drawing system. Reprinted with permission from ref (213). Copyright 2017 Wiley-VCH. Reprinted with permission from ref (214). Copyright 2020 American Chemical Society. Reprinted with permission from ref (215). Copyright 2013 Wiley-VCH.

Figure 33

Shearing orientation controls of organic semiconductor films: (A) single-step solution shearing; (B) dynamic-template-directed coating. Reprinted with permission from ref (216). Copyright 2016 American Chemical Society. Reproduced under terms of the CC-BY license from ref (217), 2017 Springer-Nature.

Figure 34

LB method at higher temperatures; (A) high-temperature LB method (up to 100 °C); (B) hyper 100 °C LB method (more than 100 °C). Reprinted with permission from ref (218). Copyright 2020 American Chemical Society. Adapted with permission from ref (219). Copyright 2021 American Chemical Society.

Figure 35

A circular flow orientation method for polymer–semiconductor thin films using glycerol as the liquid phase. Reprinted with permission from ref (220). Copyright 2025 American Chemical Society.