A Generalized Polymer Precursor Ink Design for 3D Printing of Functional Metal Oxides

Three-dimensional-structured metal oxides have myriad applications for optoelectronic devices.Comparing to conventional lithography-based manufacturing methods which face significant challenges for 3D device architectures,additive manufacturing approaches such as direct ink writing offer convenient,on-demand manufacturing of 3D oxides with high resolutions down to sub-micrometer scales.However,the lack of a universal ink design strategy greatly limits the choices of printable oxides.Here,a universal,facile synthetic strategy is developed for direct ink writable polymer precursor inks based on metal-polymer coordination effect.Specifically,polyethyleneimine functionalized by ethylenediaminetetraacetic acid is employed as the polymer matrix for adsorbing targeted metal ions.Next,glucose is introduced as a crosslinker for endowing the polymer precursor inks with a thermosetting property required for 3D printing via the Maillard reaction.For demonstrations,binary(i.e.,ZnO,CuO,In_(2)O_(3),Ga_(2)O_(3),TiO_(2),and Y_(2)O_(3)) and ternary metal oxides(i.e.,BaTiO_(3) and SrTiO_(3)) are printed into 3D architectures with sub-micrometer resolution by extruding the inks through ultrafine nozzles.Upon thermal crosslinking and pyrolysis,the 3D microarchitectures with woodpile geometries exhibit strong light-matter coupling in the mid-infrared region.The design strategy for printable inks opens a new pathway toward 3D-printed optoelectronic devices based on functional oxides.

A Numerical Investigation of the Effects of Benign Paroxysmal Positional Vertigo on the Balance Function of the Inner Ear

A three-dimensional numerical model of the membranous labyrinth of the semicircular canal of the inner ear was established to investigate the effects of canalithiasis of BPPV on the balance function of the inner ear.The movement of otolith particles in the membranous labyrinth was simulated when a person turns his head to a specific position.The effects of otolith movements on the balance function of the inner ear were simulated for different numbers,diameters,and initial positions of otoliths.The simulation results show that the otolith diameter affects the movement duration of otoliths in the membranous labyrinth.The number and diameter of otoliths,the diameter of the membranous labyrinth,and the initial position of the otoliths can cause changes in the pressure difference on both sides of the cupula of the crista ampullaris(cupula).The latent period and onset period are related to the diameter of otolith particles and the position of the head.There is also a correlation between the severity of the disease and the diameter and number of otolith particles.

Static analysis of tympanic membrane in aero-otitis media by three-dimensional model of the middle ear

The three-dimensional(3D)model of the middle ear is of great significance to the research of middle ear related diseases.The particular focus of this work is to simulate the impact of aircraft altitude and speed changes on the tympanic membrane(TM)during the descent phase,so as to analyze the pathogenesis of aero-otitis media and the mechanical response characteristics of TM under static pressure.The simulations showed that the stress and strain of TM increase as the altitude difference and speed of the aircraft increase,and the maximum stress and strain areas are consistent with the clinical observation of TM hyperemia.Therefore,among many prevention and treatment measures of aero-otitis media,it is a therapeutic method to directly balance the pressure difference between the inner and outer TM.

Multimaterial Embedded 3D Printing of Composite Reinforced Soft Actuators

Soft pneumatic actuators(SPAs)have attracted enormous attention in the growing field of robotics.Among different SPAs,composite reinforced actuators(CRAs)are widely used because of their simple structure and high controllability.However,multistep molding,a time-consuming method,is still the predominant fabrication method.Here,we propose a multimaterial embedded printing method(ME3P)to fabricate CRAs.In comparison with other 3-dimensional printing methods,our method improves fabrication flexibility greatly.Via the design and fabrication of the reinforced composites’patterns and different geometries of the soft body,we demonstrate actuators with programmable responses(elongation,contraction,twisting,bending,and helical and omnidirectional bending).Finite element analysis is employed for the prediction of pneumatic responses and the inverse design of actuators based on specific actuation needs.Lastly,we use tube-crawling robots as a model system to demonstrate our ability to fabricate complex soft robots for practical applications.This work demonstrates the versatility of ME3P for the future manufacturing of CRA-based soft robots.