Adaptive molecular self-assemblies provide possibility of constructing smart and functional materials in a non-covalent bottom-up manner. Exploiting the intrinsic properties of responsiveness of non-covalent interactions, a great number of fancy self-assemblies have been achieved. In this review, we try to highlight the recent advances in this field. The following contents are focused: (1) environmental adaptiveness, including smart self-assemblies adaptive to pH, temperature, pressure, and moisture; (2) special chemical adaptiveness, including nanostructures adaptive to important chemicals, such as enzymes, CO₂, metal ions, redox agents, explosives, biomolecules; (3) field adaptiveness, including self-assembled materials that are capable of adapting to external fields such as magnetic field, electric field, light irradiation, and shear forces.

Cyclodextrin (CD)/surfactant complexes were usually believed to be quite soluble in water and unable to form aggregates because of the hydrophilic outer surface. However, in this work, SDS@2β-CD complex is found to be able to self-assemble into well-defined lamellar structures in concentrated aqueous solution. The lamellae possess unprecedented in-plane solid-crystalline order in addition to classical lamellar liquid-crystalline order. Such a combination in orderliness makes the lamellar phase an intermediate phase between a solid and a liquid crystal. Upon dilution, the lamellae transform to microtubes and then to vesicles. The three classes of SDS@2β-CD aggregates share a consistent building block, the channel-type crystalline bilayer membrane. Moreover, since the outer surface of SDS@2β-CD is hydrophilic, its self-assembly behavior, unlike traditional amphiphilic assembly, does not rely on the hydrophobic effect. Therefore, the present nonamphiphilic self-assembly of SDS@2β-CD is envisioned to open new possibilities for self-assembly chemistry.

In this work, we report a thermo-responsive phase transition from a viscoelastic wormlike micelle solution to an elastic hydrogel in a mixture of an imidazole-type surfactant, 1-hexadecyl-3-methylimidazolium bromide (C₁₆MIMBr), and sodium salicylate (NaSal). Above the critical temperature T_gel, the sample exhibits characteristic wormlike micelle features with strong viscoelastic properties. As the temperature was lowered below the T_gel, the viscoelastic solution transforms into an elastic hydrogel with a remarkable elastic modulus increase. Polarization microscopy, SEM, and XRD were employed to reveal the morphology and molecular arrangement of the organized microstructures in the hydrogel. The unexpected phase transition from viscoelastic solution to hydrogel can be attributed to the crystallization of wormlike micelles, which is related to the strong synergic interaction between the surfactant and hydrotrope.

The creation of photo-modulated multi-state and multi-scale molecular self-assemblies was realized by the ingenuous utilization of a binary-state molecular switch, sodium (4-phenylazo-phenoxy)-acetate (AzoNa). Depending on the irradiation time, the binary state of the azobenzene group (i.e. trans/cis isomerization) can be exploited to generate multi-state nanostructures (including wormlike micelle, vesicle, lamellar structure, small micelle) by the coupling of conventional surfactant CTAB. Meanwhile, the conformation transition of azobenzene at molecular scale (∼Å), stimulated by light input can be amplified to regulate molecular architectures at mesoscopic scale (from nanometer to micrometer), leading to significant changes in solution property at macroscopic scale (naked-eye visible scale). By exposing to UV or visible light, the multi-state and multi-scale molecular self-assemblies can be reversibly controlled. It is proposed that light-triggered structural changes in the dipole moment and geometry of azobenzene group, which impart a significant effect upon molecular packing of surfactant aggregates, were responsible for this peculiar phenomenon.

Traditional aqueous self-assembly of tubular structures (as well as other aggregates) usually relies on the hydrophobic effect, a relatively weak and nondirectional interaction. The resultant aggregates are inherently soft, fluid, and less-ordered. Alternatively, we report a novel kind of nonamphiphilic self-assembly of microtubes in aqueous solutions of cyclodextrin/ionic surfactant (CD/IS) complexes. This self-assembly is driven exclusively by H-bonds, relatively strong, directional interactions. The CD/IS microtubes feature an unbundling nature, ultralong persistence lengths, highly monodispersed diameters, and remarkable rigidity. Every single CD/IS microtube is constituted by a set of coaxial, equally spaced, hollow cylinders, resembling the annular rings of trees (thus termed as “annular ring” microtubes). Furthermore, bearing in mind the fundamental difference between the amphiphilic counterpart in driving forces, this H-bond-driven hydrophilic self-assembly is envisioned to complement its counterpart and expand the field of molecular self-assembly.

Substrate-supported noble metallic nanoparticles have received intense attention owing to their great potential in various applications. In this work, silica nanotube-supported metallic nanoparticles (i.e., Au, Ag, and Pd) are synthesized by in situ reducing metal ions into nanoparticles on the nanotube surface. The silica nanotubes are prepared through the traditional sol–gel approach using laminated nanoribbons as soft templates, which are self-assembled from dipeptide-amphiphiles. The surface of silica nanotubes is functionalized to display amino groups, which serve as active sites to host metallic particles. By changing the preparation conditions, the wall thickness of silica nanotubes is adjusted and the density of metallic nanoparticles on silica surface is facilely tuned. Finally the metallic nanoparticle-coated silica nanotubes are proven to be applicable in recyclable catalysis of 4-nitrophenol (4-NP) reduction.