Macroscopic supramolecular assembly (MSA) is a recent advance in supramolecular chemistry that involves associating large building blocks with a size larger than 10 µm through noncovalent interactions. However, until now the applicable material system is rather limited to hydrogels, and MSA of rigid materials with supramolecular interactions widely used in molecular assembly has rarely been reported due to the difficulty in achieving multivalency between rigid surfaces. Herein, the concept of flexible spacing coating is applied with highly flowable properties, and the electrostatic-interaction-driven MSA of relatively rigid polydimethylsiloxane building blocks is demonstrated. With the flexible spacing coating of a polyelectrolyte multilayer, the oppositely charged rigid building blocks can realize MSA under shaking in water for 5 min. The major contribution of the electrostatic interaction is confirmed by both qualitative controlled MSA experiments in other solvents, disassembly in ionic solution and quantitative results with an in situ force measurement method.

The photothermal Marangoni effect enables direct light-to-work conversion, which is significant for realizing the self-propulsion of objects in a noncontact, controllable, and continuous manner. Many promising applications have been demonstrated in micro- and nanomachines, light-driven actuators, cargo transport, and gear transmission. Currently, the related studies about photothermal Marangoni effect-induced self-propulsion, especially rotational motions, remain focused on developing the novel photothermal materials, the structural designs, and the controllable self-propulsion modes. However, extending the related research from the laboratory practice to practical application remains a challenge. Herein, we combined the photothermal Marangoni effect-induced self-propulsion with the triboelectric nanogenerator technology for sunlight intensity determination. Photothermal black silicon, superhydrophobic copper foam with drag-reducing property, and triboelectric polytetra­fluoroethylene film were integrated to fabricate a triboelectric nanogenerator. The photothermal-Marangoni-driven triboelectric nanogenerator (PMD-TENG) utilizes the photothermal Marangoni effect-induced self-propulsion to realize the relative motion between the triboelectric layer and the electrode, converting light into electrical signals, with a peak value of 2.35 V. The period of the output electrical signal has an excellent linear relationship with the light intensity. The accessible electrical signal generation strategy proposed here provides a new application for the photothermal Marangoni effect, which could further inspire the practical applications of the self-powered system based on the photothermal Marangoni effect, such as intelligent farming.

No abstract

Recently, the global warming and climate changes have aroused focus of attentions. Hence, there is an increased demand to capture, utilize, and sequestrate the greenhouse gas, i.e., carbon dioxide (CO2), for promising applications. Functionally cooperating mini‐generators are a kind of self‐propelled smart devices that can harvest environmental energy and convert it to electricity through Faraday's law. But traditional mini‐generators are based on an energy‐consuming process appealing for energy consumption from high‐grade state to low‐grade one. Herein, a mini‐generator based on photosynthesis with CO2 as the fuel is designed. The generator can convert the internal energy of O2 bubbles produced by photosynthesis to electricity. This is an energy conversion from the lowest energy state to the applicable energy. Based on the high‐efficiency photosynthesis of hydrophyte, spontaneously water‐dissolved CO2 can afford to induce regularly cycled surfacing‐diving motion, and the induced electrical output can simultaneously actuate multiple electronic components. Owing to the weather sensitivity of the photosynthesis, the system can be used to monitor weather through reading the changes of output electrical signals. By integrating the artificial smart device with natural plants, this research will promote the applications of miniaturized devices toward green development.

Using a panel of China's 31 provinces over 1978-2008, we examine the effects of entrepreneurship on economic growth in the context of China's transformation from a centrally planned to a market-oriented economy. We divide entrepreneurship into two types: one is business creation and the other is innovation. Our GMM estimation results show that both types of entrepreneurship have significantly positive effects on growth rate of China's GDP per capita over the sample period. Specifically, annual growth rate will increase by 0.8-1.4 percentage points if business creation entrepreneurship (measured by non-public employment share in total urban employment) increases by 10 percentage points. And annual growth rate will increase by 0.12-0.16 percentage points if innovation entrepreneurship (measured by number of patents granted) increases by 10 percent. Our results are robust even when we control for different sets of demographical and institutional variables. China's experience shows that an authoritarian political regime does not conflict with entrepreneurs' role.