Muscle-fiber array inspired, multiple-mode, pneumatic artificial muscles through planar design and one-step rolling fabrication

Although the advances in artificial muscles enable creating soft robots with biological dexterity and self-adaption in unstructured environments, producing scalable artificial muscles with multiple-mode actuations is still elusive. Inspired by muscle-fiber arrays in muscular hydrostats, we present a class of versatile artificial muscles, called MAIPAMs (Muscle-fiber Array Inspired Pneumatic Artificial Muscles), capable of multiple-mode actuations (such as parallel elongation-bending-spiraling actuations, parallel 10 bending actuations, and cascaded elongation-bending-spiraling actuations). Our MAIPAMs mainly consist of active 3D elastomer-balloon arrays reinforced by a passive elastomer membrane, which is achieved through a planar design and one-step rolling fabrication approach. We introduce the prototypical designs of MAIPAMs and demonstrate their muscle-mimic structures and versatility, as well as their scalable ability to integrate flexible while un-stretchable layers for contraction and twisting actuations and compliant electrodes for self-sensing. We further demonstrate that this class of artificial muscles shows promising potentials for versatile robotic applications, such as carrying a camera for recording videos, gripping and manipulating objects, and climbing a pipe-line.

Exceptional interfacial solar evaporation via heteromorphic PTFE/CNT hollow fiber arrays

An extra energy field from the absorptive base is created, and 360° evaporation is achieved by a versatile heteromorphic array configuration.

Insect Cuticular Chitin Contributes to Form and Function

: Chitin contributes to the rigidity of the insect cuticle and serves as an attachment matrix for other cuticular proteins. Deficiency of chitin results in abnormal embryos, cuticular structural defects and growth arrest. When chitin is not turned over during molting, the developing insect is trapped inside the old cuticle. Partial deacetylation of cuticular chitin is also required for proper laminar organization of the cuticle and vertical pore canals, molting, and locomotion. Thus, chitin and its modifications strongly influence the structure of the exoskeleton as well as the physiological functions of the insect. : Internal tendons and specialized epithelial cells called “tendon cells” that arise from the outer layer of epidermal cells provide attachment sites at both ends of adult limb muscles. Membrane processes emanating from both tendon and muscle cells interdigitate extensively to strengthen the attachment of muscles to the extracellular matrix (ECM). Protein ligands that bind to membrane-bound integrin complexes further enhance the adhesion between muscles and tendons. Tendon cells contain F-actin fiber arrays that contribute to their rigidity. In the cytoplasm of muscle cells, proteins such as talin and other proteins provide attachment sites for cytoskeletal actin, thereby increasing integrin binding and activation to mechanically couple the ECM with actin in muscle cells. Mutations in integrins and their ligands, as well as depletion of chitin deacetylases, result in defective locomotion and muscle detachment from the ECM. Thus, chitin in the cuticle and chitin deacetylases strongly influence the shape and functions of the exoskeleton as well as locomotion of insects.

Inflight fiber printing toward array and 3D optoelectronic and sensing architectures

Scalability and device integration have been prevailing issues limiting our ability in harnessing the potential of small-diameter conducting fibers. We report inflight fiber printing (iFP), a one-step process that integrates conducting fiber production and fiber-to-circuit connection. Inorganic (silver) or organic {PEDOT:PSS [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate]} fibers with 1- to 3-μm diameters are fabricated, with the fiber arrays exhibiting more than 95% transmittance (350 to 750 nm). The high surface area–to–volume ratio, permissiveness, and transparency of the fiber arrays were exploited to construct sensing and optoelectronic architectures. We show the PEDOT:PSS fibers as a cell-interfaced impedimetric sensor, a three-dimensional (3D) moisture flow sensor, and noncontact, wearable/portable respiratory sensors. The capability to design suspended fibers, networks of homo cross-junctions and hetero cross-junctions, and coupling iFP fibers with 3D-printed parts paves the way to additive manufacturing of fiber-based 3D devices with multilatitude functions and superior spatiotemporal resolution, beyond conventional film-based device architectures.