Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The state-of-the-art atomic force microscopy allows us to observe inner structures of single molecules. Such observation is quite beneficial to study single and self-assembled molecules on surface as well as on-surface chemical reaction. This focus review describes recent technical improvement and achievements in the field of on-surface molecule studied with high-resolution atomic force microscopy.
Although conventional polymer gels are known as mechanically weak materials, their fracture toughness can be effectively improved by introducing weak and brittle bonds into soft and stretchy polymer networks. This toughening method, denoted as the ‘sacrificial bond principle’, has been recently proposed. In this focus review, I describe some extremely tough gels prepared using this principle, e.g., double- or multiple-network gels with high water content featuring covalent sacrificial bonds, self-healing polyampholyte gels containing ionic sacrificial bonds and PDGI/PAAm gels based on hydrophobic sacrificial bonds exhibiting stress-responsive structural colors.
Theoretical models for thermo-sensitive hydrogels in pure water and in mixed solvent of water and methanol, and for thermo-sensitive copolymer in water are developed based on the concept of cooperative hydration of thermo-sensitive water-soluble polymers. The high-temperature collapse in water and the reentrant volume phase transition in water/methanol mixtures of poly(N-isopropylacrylamide) gels, and the phase behavior of statistical random copolymers of N-isopropylacrylamide and N,N-diethylacrylamide are theoretically studied.
In this focus review, our recent investigations into the deformation and fracture processes of crystalline polymers using coarse-grained molecular dynamics simulations are described. The lamellar structure of polyethylene, a fundamental structural feature of this polymer, is successfully reproduced. Then, a stress– strain curve that exhibited good consistency with that observed experimentally is obtained. Molecular simulations are a powerful tool for elucidating the mechanisms of the deformation and fracture processes of crystalline polymers at the molecular level and this review will contribute to the development of this field of research.
