Liquid–metal-bridge∼island design: seamless integration of intrinsically stretchable liquid metal circuits and mechanically deformable structures for ultra-stretchable all-solid-state rechargeable Zn–air battery arrays

The demonstrated “liquid-metal-bridge∼island” architecture enables the fabrication of ultra-stretchable solid-state micro-Zn–air battery arrays with tunable open circuit voltage/peak power (1.35–5.24 V/38–145 mW), large elongation (400%), and excellent integration capability.

Synthesis and Properties of Cyclopentyl Cardo-Type Polyimides Based on Dicyclopentadiene

A crucial polymer intermediate, 4-[1-(4-hydroxyphenyl)cyclopentyl]-phenol (bisphenol CP), was developed from dicyclopentadiene (DCPD), a key byproduct of the C5 fraction in petrochemicals. On the basis of bisphenol CP, a diamine, 4,4′-((cyclopentane-1,1-diylbis(4,1-phenylene))bis(oxy))-dianiline (cyclopentyl diamine; CPDA) was subsequently obtained through a nucleophilic substitution of bisphenol CP, followed by the hydrogenation process. By using the CPDA diamine, a series of polyimides with cyclopentyl (cardo) units on the backbone were prepared along with a reference polyimide (API-6F) based on 4,4′-(4,4′-(propane-2,2-diyl)bis(4,1-phenylene))bis(oxy)dianiline (BPAA), and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) for the exploration of structure-properties relationship. Thanks to the presence of cyclopentyl units, this type of cardo polyimides exhibited comparable tensile properties, especially a large elongation (25.4%). It is also worth noting that CPI-6F exhibited better solubility in organic solvents, such as NMP, DMAc, THF, and chloroform, than the other PIs. Gas separation properties were also evaluated for these cardo-type polyimides.

Phase Stability and Mechanical Properties of Metastable Ti-X-Sn-Zr (x=Cr, Nb or Fe) Alloys

Metastable beta Ti-Cr-Sn-Zr alloys used as biomaterial show low Young’s modulus and super-elasticity according to the phase stability of their beta phase. In this study, we substituted Nb and Fe for Cr in metastable beta Ti-2Cr-6Sn-45Zr alloy and investigated their effect. We investigated how the added amount of Cr, Nb and Fe influences the phase stability and the properties of low Young’s modulus and super-elasticity in Ti-x-Sn-Zr (x=Cr, Nb or Fe) alloys. The Young’s modulus of a Ti-x-Sn-Zr (x=Cr, Nb or Fe) alloy decreases with the addition of Cr, Nb or Fe. However, the Young’s modulus of a Ti-x-Sn-Zr (x=Cr, Nb or Fe) alloy increases with the addition of Cr, Nb or Fe after showing own minimum value respectively. Minimum Young’s modulus of several Ti-x-Sn-Zr (x=Cr, Nb or Fe) alloys were under 50GPa. The required amount of Cr, Nb or Fe in the Ti-x-Sn-Zr (x=Cr, Nb or Fe) alloy having minimum Young’s modulus is different according to the beta stabilizing ability of each element. Fe amounts were the smallest and Nb amounts were the largest. Ti-x-Sn-Zr (x=Cr, Nb or Fe) alloy with minimum Young’s modulus shows a stress-induced martensitic transformation. However, only Ti-Cr-Sn-Zr alloys showed definite super-elasticity. The recovered strain by super-elasticity is small in Ti-Nb-Sn-Zr alloy. Ti-Fe-Sn-Zr alloy didn’t show super-elasticity or large elongation.

Effect of Sn Addition on Superplastic Properties of Zn-22mass%Al Eutectoid Alloy

Superplastic behavior of a Zn 22 mass % Al eutectoid alloy (SPZ) with small addition of Sn (SPZSn) was investigated. Granular grain size of about 0.3 μm was obtained by water quench after annealing SPZ and SPZ05Sn (addition of 0.05 mass % Sn into the SPZ) at 653 K for 2 h. The fundamental microstructure of the SPZ05Sn was similar to that of the SPZ, but, microstructure observation by STEM showed additive Sn was present at the α’ grain boundary in the SPZ05Sn. Excellent high strain rate superplasticity was achieved in the SPZ05Sn, with elongation of more than 1300 % at 523 K at strain rate of 10-1 S-1. Furthermore, large elongation of about 1100 % was recorded at 473 K at strain rate of 10-1 S-1. The large elongation and high strain rate sensitivity value of the SPZ05Sn tend to shift to higher strain rate region as compared to those of the SPZ. It was considered that the small addition of Sn into the SPZ effectively suppressed the grain growth of α and β phase during the superplastic deformation, because granular grains less than 2 μm is maintained after superplastic deformation at 523 K.