Macroscopic supramolecular assembly (MSA) is a recent development in supramolecular chemistry to associate visible building blocks through non-covalent interactions in a multivalent manner. Although various substrates (e.g. hydrogels, rigid materials) have been used, a general design rule of building blocks in MSA systems and interpretation of the assembly mechanism are lacking and are required. Herein we design three model systems with varied elastic modulus and correlated the MSA probability with the elasticity. Based on the effects of substrate deformability on multivalency, we have proposed an elastic-modulus-dependent rule that building blocks below a critical modulus of 2.5 MPa can achieve MSA for the used host/guest system. Moreover, this MSA rule applies well to the design of materials for fast underwater adhesion: Soft substrates (0.5 MPa) can achieve underwater adhesion within 10 s with one order of magnitude higher strength than that of rigid substrates (2.5 MPa).

Superhydrophobic to neutral water droplets, superhydrophilic to acidic or basic. This double transition of surface wettability in response to a single stimulus - pH - is demonstrated for the first time. The smart surface is composed of a rough gold surface modified with a self-assembled monolayer (SAM) containing three thiols, HS(CH2 )11 CH3 , HS(CH2 )10 COOH, and HS(CH2 )11 NH2 . A ternary diagram is generated that describes wettability as a function of the SAM composition and the pH of the surrounding solution.

To handle the serious issue of increasing oil spill accidents, many strategies have been proposed to either clean spilt oil or separate water/oil mixture. Especially, superhydrophilic/underwater superoleophobic smart materials have recently shown advantages in overcoming problems of oil blocking and water barriers during conventional oil/water-separating process of oil-rich mixtures with superhydrophobic/superoleophilic materials. However, to the best of our knowledge, no prior reports have detailed smart materials with the wetting properties of superhydrophobic/superoleophilic that can be applied in continuous in situ separations of oil/water/oil ternary mixtures, which are common in practical oil spill cases. Herein, we describe the fabrication and efficacy of a pH-responsive smart device for continuous in situ separations of such oil/water/oil ternary mixtures without the need for ex situ treatments. In air, the superhydrophobic/superoleophilic surface of the device allowed dichloromethane to permeate through while preventing water from passing. The superhydrophilicity/underwater superoleophobicity of the device surface following alkaline treatments prevented the passage of hexane while allowing water to penetrate the device.

Macroscopic supramolecular assembly (MSA) represents a new advancement in supramolecular chemistry involving building blocks with sizes beyond tens of micrometers associating through noncovalent interactions. MSA is established as a unique method to fabricate supramolecularly assembled materials by shortening the length scale between bulk materials and building blocks. However, improving the precise alignment during assembly to form orderly assembled structures remains a challenge. Although the pretreatment of building blocks can ameliorate order to a certain degree, defects or mismatching still exists, which limits the practical applications of MSA. Therefore, an iterative poststrategy is proposed, where self-correction based on dynamic assembly/disassembly is applied to achieve precise, massive, and parallel assembly. The self-correction process consists of two key steps: the identification of poorly ordered structures and the selective correction of these structures. This study develops a diffusion-kinetics-dependent disassembly to well identify the poorly aligned structures and correct these structures through iterations of disassembly/reassembly in a programmed fashion. Finally, a massive and parallel assembly of 100 precise dimers over eight iteration cycles is achieved, thus providing a powerful solution to the problem of processing insensitivity to errors in self-assembly-related methods.

A "smart", functionally cooperating device consisting of a platinum strip and steel bead inside a nickel foam cube with a temperature-responsive polymer coating shows a diving-surfacing cycle when the water temperature first falls below and then rises above the lower critical solution temperature (LCST) of the polymer, which marks the change from superhydrophobicity to superhydrophilicity. Furthermore, the smart device allows a cycled directional delivery of lipophilic molecules between three phases.

Chemical energy supplied by the catalytic decomposition of H2O2 is introduced into macroscopic building blocks, which self-propel, interact with each other, and finally assemble into ordered and advanced structures. The geometry is highly dependent on the way that the catalyst is loaded. The integration of catalyst and building block provides assembling component as well as its energy of motion.

A smart device that can dive or surface in aqueous medium has been developed by combining a pH-responsive surface with acid-responsive magnesium. The diving-surfacing cycles can be used to convert chemical energy into electricity. During the diving-surfacing motion, the smart device cuts magnetic flux lines and produces a current, demonstrating that motional energy can be realized by consuming chemical energy of magnesium, thus producing electricity.

To handle serious underwater oil spills, we have designed a functionally integrated device which can continuously clean up spilled oil underwater or on the water's surface in a directional manner, guided by a magnetic field, collecting the oil into the interior of the device and recycling it. The collecting efficiency is higher than 90%.