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Native spider silk has desirable mechanical properties, but these are challenging to replicate in an artificial material. Here, the authors report the use of a microfluidic system to create continuous fibers based on recombinant spidroin.

The role of strain rate (\(\dot \varepsilon\)) in strain induced crystallization (SIC) of vulcanized natural rubber (NR) and synthetic isoprene rubber (IR) was studied by in-situ wide angle X-ray scattering (WAXS). The nucleation rate (I) was determined by measuring the slope on the plot of the scattering intensity (I_X) as a function of time (t). Various I values were determined for various \(\dot \varepsilon\). On the plot of I vs. \(\dot \varepsilon\), we found that I is proportional to \(\dot \varepsilon\); I ∝ \(\dot \varepsilon\)

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The change of ultra-small-angle X-ray scattering (USAXS) image after necking was taken for poly(ethylene terephthalate) (PET) and poly(phenylene sulfide) (PPS) fibers. USAXS pattern of PPS shows three streaks, which were meridional and equatorial streaks and total reflection. In addition to the three streaks observed for PPS, USAXS pattern of PET shows a layer-lined streak. Far stronger meridional streak of PPS means the periodic density deviation preliminary formed in the as-spun fiber, and the layer-lined USAXS streak of PET could be explained by the periodic bundle of a fibrillar-shaped smectic phase.

We carried out isothermal crystallization experiment for isotactic polypropylene (iPP) containing 1,3:2,4-bis(p-methylbenzylidene)sorbitol (PDTS) as a nucleation additive. Avrami analysis for iPP/PDTS systems showed that the Avrami exponent decreased from 3.5–4 to 2 with decrease of the crystallization temperature T_c only by 4 °C, being contrasted with iPP, where the exponent was 4 for all T_c. This study shows that the iPP/PDTS crystallization kinetics and its temperature sensitiveness were determined by the competition between two events: PDTS network growth and iPP crystallization.

This study demonstrated that synchrotron radiation ultra-small angle X-ray scattering (SR-USAXS) enable us to evaluate the outermost surface and ‘buried’ periodic structure without any pretreatment and sample damage. Surface and ‘buried’ nanostructure were fabricated on poly(lactic acid) film by nanoimprint lithography. The resulting films were characterized by SR-USAXS. The size of surface and ‘buried’ structure were successfully determined by the analysis of scattering pattern.

A new beamline called the frontier soft-material beamline at BL03XU for soft materials was recently installed at SPring-8, using an in-vacuum undulator. The photon flux can reach 10¹³ photons sec⁻¹ and the energy resolution is about 10⁻⁴ at an energy of 12.4 keV. The present paper introduces details on the instrumental and some of the first scattering data measured at BL03XU, revealing its cutting-edge design and high performance.

The new experimental system has been launched by coupling with the measurement techniques, which are grazing incidence small/wide-angle X-ray Scattering (GISWAXS) and grazing incidence X-ray diffraction (GIXD), as well as X-ray reflectivity (XR), at the BL03XU of SPring-8. Using this integrated system, we can achieve to measure the hierarchical structure of the same sample.

We present a mechanistic study of the structural formation on the curing process of the liquid–crystalline epoxy with the simultaneous measurement of SAXS/WAXS using synchrotron radiation. The following behaviors were revealed: after the temperature-jump to the curing temperature, first the system forms the nematic domains; the nematic-to-smectic conversion proceeds after an incubation period; the transformation continues beyond the conversion of 80% of epoxide-amine bond formation and corresponding entire polymer network formation.

Solid-state films made from deoxyribonucleic acid where the mechanical properties are controllable, from glassy to rubbery, via semicrystalline by simply regulating the water content in the film.

X-ray scattering from an organogel made from discotic triazine triamide was measured at SPring-8 at a quite wide q range of 0.050 nm⁻¹ <q <20 nm⁻¹. Analyses revealed (1) an amorphous nature of the molecular stacking at a distance of 0.32 nm, (2) the presence of a semiflexible rod-like scattering object with a radius of 1.3 nm and a Kuhn length of 55 nm and (3) branching of the cylinder formed at the gel state.

Spider silk is well known for its high toughness. Here, a comprehensive study of the simultaneous effect of strain rate and humidity on toughness is reported, revealing that toughness is highest under mildly humid conditions and at high strain rates, similar conditions to those in nature.

Natural rubber exhibits the strain-induced crystallization (SIC). By using WAXD, the orientation of NR crystal formed by SIC under planar elongation was revisited. We found that the orientational state of the crystal lattice possesses a continuous margin of the orientation angle between 6.4 and 19.6° for the ac plane with respect to the surface of the specimen sheet in the real NR specimen. This orientational state could be accomplished as a result of balancing the preferential parallel orientation of (120) planes (the slip planes) and C = C planes with respect to the surface of the specimen sheet.

Photooxidation and fragmentation behaviors of itPP were studied. Photooxidation likely occurred in the amorphous regions of itPP due to the higher oxygen diffusion. Surface deterioration was observed on the UV-exposed itPP films. Pressed films exhibited much denser cracks compared to uniaxially oriented itPP films. Notably, cracks in the uniaxially oriented itPP films were formed along the direction of orientation and decreased with increasing draw ratio. The crystalline structure and oriented molecular chains notably inhibited the photooxidative degradation and fragmentation of the itPP films.

The in situ wide-angle (WAXD) and small-angle X-ray scattering (SAXS) measurements have been performed using a synchrotron microbeam technique for the melt-isothermally-growing iPP spherulites. The thus-collected data were found to be classified into three sets of totally different WAXD/SAXS patterns, from which the three different orientation modes of the stacked lamellae and related crystallographic axes were deduced. These structural information allowed us to discuss the growth mechanism of stacked lamellae in the iPP spherulites from the microscopic point of view.

A degradable cross-linked polybutadiene was synthesized using a peptide-based cross-linker. As a degradable cross-linker, we synthesized poly(L-cysteine) (polyCys) by papain-catalyzed chemoenzymatic polymerization. The thiol-ene reaction between polybutadiene and polyCys was conducted in the presence of a radical initiator, resulting in the formation of an insoluble polybutadiene gel. The successful cross-linking and network formation was confirmed by Raman spectroscopy and viscoelastic analysis. Dynamic viscoelastic measurements of the cross-linked polybutadiene revealed the disappearance of slow relaxation mode. The polyCys-linked polybutadiene underwent degradation through acidic hydrolysis, allowing the recovery of soluble polybutadiene.

The 2D WAXD/SAXS data collected using a synchrotron X-ray microbeam technique revealed the details of the lamellar twisting phenomenon of high-density polyethylene spherulites. The molecular mechanics calculation, performed for large aggregation models of alkane chains having bulky head groups or folded polyethylene chains, has successfully reproduced the lamellar twisting pitch of a few μm, as extracted from the X–ray data analysis.

Inspired by the natural spinning process, we developed an aqueous spinning system with a citrate/polyethylene glycol buffer for highly extensible silk fibers. This system enabled tuning of the induction of crystallization through the buffer conditions.

Polypeptides containing periodic aromatic residues, 4-aminobenzoic acid (Abz), in their main chains were synthesized via papain-catalyzed chemoenzymatic polymerization of tripeptide ester monomers under moderate conditions in aqueous buffers. The secondary structures of the Abz-containing polypeptides were investigated by IR and wide-angle X-ray diffraction analysis. The WAXD profile of poly(GlyAbzGly) was similar to that of polyGly, whereas poly(AlaAbzAla) adopted a sheet-like structure similar to the β-sheet of polyAla.

We studied the elongational crystallization of poly(ethylene terephthalate) (PET) from the supercooled melt. We found that the novel three-dimensional (3D) structure of “nano-oriented crystals (NOCs)” was formed, where nanocrystals (NCs) were arranged on monoclinic lattice. We observed the structure and morphology of NOCs by means of polarizing optical microscope and small/wide angle X-ray scatterings. We clarified the important role of a primary structure of the plate-like benzene ring in the formation of the NOCs of PET. We also showed high performance of NOCs of PET, such as high heat resistance temperature and high maximum tensile stress.

We studied the formation mechanism of ‘nano-oriented crystals (NOCs)’ of isotactic polypropylene in elongational crystallization through crystallization temperature dependence of NOCs formation. We proposed a ‘chain reaction model’ of NOCs formation: The local oriented melt is formed by the melt elongation, which significantly accelerates nucleation; and, generated nuclei accelerate formation of local oriented melt that accelerates nucleation again. We obtained the nucleation rate (I_obs) of NOCs against the degree of supercooling (ΔT). Here, an equilibrium melting temperature in the oriented melt T_m⁰=220 ^°C is estimated from observation of NOCs formation. I_obs was well fitted by well-known equation of for homogeneous nucleation in classical nucleation theory, where C is a constant. Therefore, we concluded that NOCs formation is mainly controlled by the homogeneous nucleation process.

The chain dimension of surface-grafted poly[3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate)] brush on silica nanoparticles in aqueous NaCl solution was precisely estimated by dynamic light scattering and synchrotron radiation small-angle X-ray scattering measurements to reveal large dependency on salt concentration. On the other hand, we confirmed that the chain dimension of poly(2-methacryloyloxyethyl phosphorylcholine) brush in aqueous solution was hardly affected by salt concentration.

We succeeded in elongational crystallization of isotactic polypropylene (iPP) by compressing the supercooled melt. When the elongational strain rate ( ) surpassed a critical value ( *=2×10² s⁻¹), crystallization behavior and structure discontinuously changed. The induction time decreased by 10⁻⁶ times (Figure), the crystal size decreased by 10⁻³ times and morphology changed from spherulites to ‘nano-oriented crystals (NOCs)’. It is concluded that large induced the ‘oriented melt’ and NOCs. The NOCs showed high crystallinity and ultra-high performances, such as high tensile stress (210 MPa).