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This paper reviews our X-ray and neutron scattering experiments on the molecular structure and dynamics of a supramolecular assembly, polyrotaxane (PR) composed of polyethylene glycol (PEG) and α-cyclodextrin (CD). Inclusion complex formation with CDs increases the stiffness of the PEG backbone and restricts the diffusion of the PEG monomers that are covered by or in close proximity to the CD molecules.
Biological membranes that tailor their morphology to environmental stimuli are nature’s ultimate smart molecular systems. This focused review describes the design and function of smart biomembrane nanohybrids. Specifically, liposomes and exosomes can be functionalized with inorganic substances and polymers to afford hybridized artificial cell membranes. These membranes have a tailorable morphology and can incorporate functional integral membrane proteins.
Poly(ethylene-2,6-naphthalate) (PEN) nanofibers were prepared by carbon dioxide laser supersonic drawing (CLSD). The CLSD method was carried out by irradiating the as-spun PEN fiber with a laser in a low-temperature supersonic jet, which was generated by blowing the air from the fiber supplying orifice into a vacuum chamber. The DSC curve of the PEN nanofibers produced by CLSD showed two melting peaks: 260 °C and 285 °C. The increase in melting temperature is attributed to the supramolecular sequence effect, which is a nanoscale effect.
Thin film aromatic polyimides were quantitatively analyzed by grazing-incidence X-ray diffraction (GI-XRD), variable-temperature infrared p-polarized multiple-angle resolution spectroscopy (VT-pMAIRS), and spectroscopic ellipsometry (SE) methods. Combining VT-pMAIRS and GI-XRD revealed characteristic heterogeneous structures comprising non-oriented amorphous and oriented liquid-crystalline glass regions. Additionally, SE indicated that the film involved anisotropic-shaped void inducing form-birefringence. Such an excess of birefringence can make it difficult to estimate orientational order using birefringence measurement. This methodology presented here will remarkably contribute to general structural analyses of all intriguing thin-film polymers with characteristic heterogeneity.
The silicone rubber materials with foam/solid alternating multilayered structure have been constructed by combining two methods of the multilayered hot-pressing and supercritical carbon dioxide (SCCO2) foaming. The growth of the cell is restrained by the solid layer, resulting in a decrease of the cell size. In addition, the introduction of the solid layer can effectively improve the mechanical properties of the microcellular silicone rubber foam. The experimental results are analyzed by finite element analysis (FEA).
Dissolved polymers directed molecular crystallization behavior under dilute and crowding conditions. Larger poly(ethylene glycol)s (PEGs) accelerated caffeine crystal formation in the dilute regime of PEG solutions, which was attributed to the depletion attraction that promoted caffeine cluster aggregation into crystal nuclei. In the semidilute regime, the crystal formation rate was insensitive to the molecular weight of PEGs. This observation was consistent with polymer blob properties, which govern depletion attraction and maintain a constant size at a given polymer concentration, irrespective of molecular weight in the semidilute regime.
As a surface modifier, poly[oligo(2-ethyl-2-oxazoline) methacrylate] (P[O(Ox)nMA]) with two different degrees of polymerization (n = 7 and 19) of the side chain were mixed into poly(methyl methacrylate) (PMMA). Once the PMMA/P[O(Ox)nMA] films contacted with water, the surface was reorganized due to the migration of P[O(Ox)nMA]. The extent of the surface segregation was more remarkable for P[O(Ox)7MA] than P[O(Ox)19MA] due to the entropic factor, resulting that the fibroblast adhesion on the film were much better suppressed for P[O(Ox)7MA] than P[O(Ox)19MA].
Amphiphilic thermoresponsive copolymer bottlebrushes based on methoxy oligo(ethylene glycol) methacrylate (MOEGM) and alkoxy(C12-C14) oligo(ethylene glycol) methacrylate (DOEGM) have been synthesized via RAFT and conventional free-radical polymerization in toluene. In water, these copolymer brushes form flower-like micelles with a hydrophobic core consisting of a polymer backbone and alkyl(C12–C14) groups and poly(ethylene glycol) linear chains and loops forming a hydrophilic shell. The size and aggregation number of the micelles depend on the copolymer composition and chain length, as well as on the synthesis method.
Using polymerase chain reaction (PCR)-mediated recombination, we prepared single ribonucleic acid (RNA) chains containing bifunctional RNA sequences involving substrate binding and phosphorescent signaling. The prepared RNAs largely maintained the functionalities of the original aptamers even after bifunctionalization. We demonstrated that the bifunctionalized RNAs can be used as phosphorescent detection probes for the target protein. Therefore, we suggested that the PCR-mediated “one stroke drawing” is a promising strategy for the preparation of RNA detection probes.
![Poly[oligo(2-ethyl-2-oxazoline) methacrylate] as a surface modifier for bioinertness](https://media.springernature.com/lw602/springer-static/image/art%3A10.1038%2Fs41428-020-00459-7/MediaObjects/41428_2020_459_Figa_HTML.png)
