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Graphene macroscopic materials have attracted tremendous attention for their fascinating performance and rich functionalities. Here, we provide an elaborate description of techniques in the fabrication of graphene macroscopic materials, focusing on the wet-spinning of 1D fibers and wet-spinning of continuous 2D films and 3D ultraflyweight aerogels. The thread of the research concepts is discussed to offer an overview of graphene macroscopic assembly. We summarize the fabrication system of wet-spinning of fiber and films, which extends to the chemistry of solvated graphene, the formation of graphene LCs, and the chemical/thermal reduction of graphene materials. The experimental details of graphene ultraflyweight aerogel are also been described. We hope that this paper can act as an experimental guidance for researchers, and become suggestive for forthcoming advances in graphene macroscopic materials. [ABSTRACT FROM AUTHOR]

Wereport knitted fabrics made from highly conductive stretchablefibers. The maximum initial conductivity of fibers synthesized bywet spinning was 17460 S cm–1with a rupture tensilestrain of 50%. The maximum strain could be increased to 490% by decreasingthe conductivity to 236 S cm–1. The knitted fabricwas mechanically and electrically reversible up to 100% tensile strainwhen coated by poly(dimethylsiloxane). The normalized resistance ofthe poly(dimethylsiloxane)-coated fabric decreased to 0.65 at 100%strain. [ABSTRACT FROM AUTHOR]

Electrospinning has been widely used to prepare polymerfiberswith diameters ranging from a few nanometers to micrometers. Whilemost studies focus on controlling the sizes and morphologies of electrospunpolymer fibers by changing electrospinning conditions, the effectof post-treatments such as thermal annealing on the properties ofelectrospun polymer fibers has been less studied. Here, we investigatethe effect of thermal annealing on the morphology changes of electrospunpolystyrene (PS) fibers on substrates. Different from annealing thefibers in a uniform environment, annealing the fibers on substratesresults in a substrate-dependent morphology transformation. When theelectrospun PS fibers are annealed on a glass substrate, wetting ofthe fibers on the glass substrate occurs. When the electrospun PSfibers are annealed on a poly(methyl methacrylate) (PMMA)-coated substrate,a Rayleigh-instability-driven morphology transformation is observed.The polymer fibers transform into hemispherical polymer particlescaused by the lower surface tension of PS than that of PMMA and theinterfacial tension between PS and PMMA. This transformation processis influenced by the annealing time and temperature. The characteristictime of the transformation process is shorter when the sample is annealedat a higher temperature because of the lower polymer viscosity. Thesize of the polymer particles fits well with the theoretical prediction,which is dependent on the initial fiber diameter and is independentof the annealing temperature. [ABSTRACT FROM AUTHOR]

Spider attachment disc silk fibers are spun into a viscous liquid that rapidly solidifies, gluing dragline silk fibers to substrates for locomotion or web construction. Here we report the identification and artificial spinning of a novel attachment disc glue silk fibroin, Pyriform Spidroin 2 (PySp2), from the golden orb weaver Nephila clavipes. MS studies support PySp2 is a constituent of the pyriform gland that is spun into attachment discs. Analysis of the PySp2 protein architecture reveals sequence divergence relative to the other silk family members, including the cob weaver glue silk fibroin PySp1. PySp2 contains internal block repeats that consist of two subrepeat units: one dominated by Ser, Gln, and Ala and the other Pro-rich. Artificial spinning of recombinant PySp2 truncations shows that the Ser-Gln-Ala-rich subrepeat is sufficient for the assembly of polymeric subunits and subsequent fiber formation. These studies support that both orb- and cob-weaving spiders have evolved highly polar block-repeat sequences with the ability to self-assemble into fibers, suggesting a strategy to allow fiber fabrication in the liquid environment of the attachment discs. [ABSTRACT FROM AUTHOR]

Regenerated silk fibroin (RSF) fibers were obtained by extruding a concentrated aqueous silk fibroin solution into an ammonium sulfate coagulation bath. A custom-made simplified industrial-type wet-spinning device with continuous mechanical postdraw was used. The effect of dope concentration, coagulation bath, extrusion rate, and postdraw treatment on the morphology of RSF fiber was examined. The results showed that although RSF fiber could be formed with dope concentration between 13 and 19% (w/w), the ones spun from 15% RSF solution showed the most regular morphology being dense and homogeneous in cross-section with a smooth surface and a uniform cylindrical shape. Though it had little effect on morphology, postdraw treatment especially under steam, significantly improved the mechanical properties of the RSF fibers. [ABSTRACT FROM AUTHOR]

The major problem associated with the production of alginate/chitosan hybridized fibers by wet spinning is the formation of gels due to ionic interactions of the oppositely charged molecules of alginate and chitosan when these two polymers are directly mixed. Here, we proposed a novel method of using chitosan in the form of an emulsion. The emulsion was prepared by adding a primary emulsion of olive oil in a sodium dodecyl sulfate (SDS) aqueous solution into a chitosan−citrate complex. The complexation of chitosan with citric acid is the key of this method. The citrate ions neutralize the positive charges of chitosan, rendering the chitosan−citrate complex to readily penetrate into the core of the SDS/olive oil micelles. The obtained emulsified chitosan−citrate complex (hereafter, the chitosan−citrate emulsion) of varying amount was then added into an alginate aqueous solution to prepare the alginate/chitosan spinning dope suspensions. The alginate/chitosan hybridized fibers showed spotty features of the emulsified chitosan−citrate complex particles locating close to the surface and the inside of the hybridized fibers. At the lowest content of incorporated chitosan (i.e., 0.5% w/w chitosan), both the tenacity and the elongation at break of the obtained chitosan-spotted alginate fibers were the greatest. Further increase in the chitosan content resulted in a monotonous decrease in the property values. Lastly, preliminary studies demonstrated that the obtained chitosan-spotted alginate fibers showed great promises as carriers for drug delivery. [ABSTRACT FROM AUTHOR]