scholarly journals Assessing the Viscoelasticity of Photopolymer Nanowires Using a Three-Parameter Solid Model for Bending Recovery Motion

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2961
Author(s):  
Jana Kubacková ◽  
Cyril Slabý ◽  
Denis Horvath ◽  
Andrej Hovan ◽  
Gergely T. Iványi ◽  
...  
Keyword(s):  
Glucose Solution ◽  
Bulk Material ◽  
Effective Elastic Modulus ◽  
Building Blocks ◽  
Solid Model ◽  
Two Photon ◽  
Notable Effect ◽  
Direct Laser ◽  
Applied Forces ◽  
Newtonian Liquids

Photopolymer nanowires prepared by two-photon polymerization direct laser writing (TPP-DLW) are the building blocks of many microstructure systems. These nanowires possess viscoelastic characteristics that define their deformations under applied forces when operated in a dynamic regime. A simple mechanical model was previously used to describe the bending recovery motion of deflected nanowire cantilevers in Newtonian liquids. The inverse problem is targeted in this work; the experimental observations are used to determine the nanowire physical characteristics. Most importantly, based on the linear three-parameter solid model, we derive explicit formulas to calculate the viscoelastic material parameters. It is shown that the effective elastic modulus of the studied nanowires is two orders of magnitude lower than measured for the bulk material. Additionally, we report on a notable effect of the surrounding aqueous glucose solution on the elasticity and the intrinsic viscosity of the studied nanowires made of Ormocomp.

scholarly journals Four-dimensional micro-building blocks

2020 ◽  
Vol 6 (3) ◽  
pp. eaav8219 ◽  
Author(s):  
T.-Y. Huang ◽  
H.-W. Huang ◽  
D. D. Jin ◽  
Q. Y. Chen ◽  
J. Y. Huang ◽  
...  
Keyword(s):  
Design Principle ◽  
Modular Design ◽  
Building Blocks ◽  
Stimuli Responsive ◽  
Race Car ◽  
Two Photon ◽  
Direct Laser ◽  
3D Printed ◽  
Reconfigurable Structures ◽  
Responsive Hydrogels

Four-dimensional (4D) printing relies on multimaterial printing, reinforcement patterns, or micro/nanofibrous additives as programmable tools to achieve desired shape reconfigurations. However, existing programming approaches still follow the so-called origami design principle to generate reconfigurable structures by self-folding stacked 2D materials, particularly at small scales. Here, we propose a programmable modular design that directly constructs 3D reconfigurable microstructures capable of sophisticated 3D-to-3D shape transformations by assembling 4D micro-building blocks. 4D direct laser writing is used to print two-photon polymerizable, stimuli-responsive hydrogels to construct building blocks at micrometer scales. Denavit-Hartenberg (DH) parameters, used to define robotic arm kinematics, are introduced as guidelines for how to assemble the micro-building blocks and plan the 3D motion of assembled chain blocks. Last, a 3D-printed microscaled transformer capable of changing its shape from a race car to a humanoid robot is devised and fabricated using the DH parameters to guide the motion of various assembled compartments.

Reaction-Diffusion Modeling of Photopolymerization During Femtosecond Projection Two-Photon Lithography

2021 ◽  
Author(s):  
Rushil Pingali ◽  
Sourabh K. Saha
Keyword(s):  
Diffusion Mechanism ◽  
Chemical Properties ◽  
Reaction Diffusion ◽  
Element Model ◽  
Polymerization Process ◽  
Layer By Layer ◽  
Length Scales ◽  
Two Photon ◽  
Reaction Diffusion Model ◽  
Direct Laser

Abstract Two-photon lithography (TPL) is a polymerization-based direct laser writing process that is capable of fabricating arbitrarily complex three-dimensional (3D) structures with submicron features. Traditional TPL techniques have limited scalability due to the slow point-by-point serial writing scheme. The femtosecond projection TPL (FP-TPL) technique increases printing rate by a thousand times by enabling layer-by-layer parallelization. However, parallelization alters the time and the length scales of the underlying polymerization process. It is therefore challenging to apply the models of serial TPL to accurately predict process outcome during FP-TPL. To solve this problem, we have generated a finite element model of the polymerization process on the time and length scales relevant to FP-TPL. The model is based on the reaction-diffusion mechanism that underlies polymerization. We have applied this model to predict the geometry of nanowires printed under a variety of conditions and compared these predictions against empirical data. Our model accurately predicts the nanowire widths. However, accuracy of aspect ratio prediction is hindered by uncertain values of the chemical properties of the photopolymer. Nevertheless, our results demonstrate that the reaction-diffusion model can accurately capture the effect of controllable parameters on FP-TPL process outcome and can therefore be used for process control and optimization.

scholarly journals Polymer-graphene composites by photocuring of a system containing benzophenone macromer

2016 ◽  
Vol 81 (9) ◽  
pp. 1055-1068
Author(s):  
Florentina Jitaru ◽  
Andreea Chibac ◽  
George Epurescu ◽  
Ioana Ion ◽  
Tinca Buruiana
Keyword(s):  
Graphene Oxide ◽  
Hybrid Composites ◽  
Two Photon ◽  
Polymerization Kinetic ◽  
Composites Materials ◽  
Femtosecond Laser Beam ◽  
Reduced Graphene ◽  
Direct Laser ◽  
Xrd Techniques ◽  
Graphene Structures

Formulations incorporating benzophenone oligodimethacrylate (BP-DMA) and graphene structures (graphene oxide/GO, reduced graphene oxide/RGO) were exposed to UV/vis irradiation or femtosecond laser beam to achieve hybrid composites. All structures were characterized through various methods including 1H NMR and FTIR spectroscopies, optical microscopy, TEM, SEM/EDAX analysis, and DSC/XRD techniques. The photopolymerization of BP-DMA in monomer compositions with and without GO or RGO was investigated by photo-DSC and FTIR methods for determining the polymerization kinetic parameters. The photopolymerization experiments revealed a good photoreactivity of the monomers (degree of conversion: 65-77%) after 1 minute exposure to UV/vis irradiation and the addition of graphene (up to 0.5%), whereas the polymerization rate varied between 0.14 and 0.1 s-1. Moreover, two-photon photopolymerization of the formulations in presence/absence of GO or RGO nanosheets (0.1 wt.%) generated 2D microstructures by direct laser writing procedure. Also, the morphology and the properties of composites materials were analyzed.

scholarly journals Two-Photon Polymerization of Albumin Hydrogel Nanowires Strengthened with Graphene Oxide

Biomimetics ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 66
Author(s):  
Nikita Nekrasov ◽  
Natalya Yakunina ◽  
Vladimir Nevolin ◽  
Ivan Bobrinetskiy ◽  
Pavel Vasilevsky ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Nanoelectromechanical Systems ◽  
Force Microscopy ◽  
Two Photon ◽  
Direct Laser ◽  
Two Photon Polymerization

Multifunctional biomaterials can pave a way to novel types of micro- and nanoelectromechanical systems providing benefits in mimicking of biological functions in implantable, wearable structures. The production of biocomposites that hold both superior electrical and mechanical properties is still a challenging task. In this study, we aim to fabricate 3D printed hydrogel from a biocomposite of bovine serum albumin with graphene oxide (BSA@GO) using femtosecond laser processing. We have developed the method for functional BSA@GO composite nanostructuring based on both two-photon polymerization of nanofilaments and direct laser writing. The atomic-force microscopy was used to probe local electrical and mechanical properties of hydrogel BSA@GO nanowires. The improved local mechanical properties demonstrate synergistic effect in interaction of femtosecond laser pulses and novel composite structure.

Design and Fabrication of Straight Waveguides, Tapers and S-Bends with Two-Photon Direct Laser Writing

2021 ◽  
Author(s):  
Tigran Baghdasaryan ◽  
Koen Vanmol ◽  
Francis Berghmans ◽  
Hugo Thienpont ◽  
Thomas Geernaert ◽  
...  
Keyword(s):  
Direct Laser Writing ◽  
Laser Writing ◽  
Two Photon ◽  
Direct Laser

Femtosecond-laser direct writing for spatially localized synthesis of PPV

2017 ◽  
Vol 5 (14) ◽  
pp. 3579-3584 ◽  
Author(s):  
Oriana I. Avila ◽  
Juliana M. P. Almeida ◽  
Franciele R. Henrique ◽  
Ruben D. Fonseca ◽  
Gustavo F. B. Almeida ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Photon Absorption ◽  
Direct Laser Writing ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Thermal Reactions ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Direct Laser ◽  
Fs Laser

Conversion of PTHT into PPV is achieved by direct laser writing. Fs-laser pulses induce photo-thermal reactions due to two-photon absorption, resulting in the microscopic control of PPV polymerization. Such methodology is a promising way towards the fabrication of arbitrary polymeric microcircuits.

Direct laser writing of synthetic poly(amino acid) hydrogels and poly(ethylene glycol) diacrylates by two-photon polymerization

2014 ◽  
Vol 43 ◽  
pp. 280-289 ◽  
Author(s):  
Elli Käpylä ◽  
Tomáš Sedlačík ◽  
Dogu Baran Aydogan ◽  
Jouko Viitanen ◽  
František Rypáček ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ethylene Glycol ◽  
Direct Laser Writing ◽  
Poly Ethylene Glycol ◽  
Laser Writing ◽  
Two Photon ◽  
Direct Laser ◽  
Poly Ethylene ◽  
Two Photon Polymerization

scholarly journals Linked topological colloids in a nematic host

2015 ◽  
Vol 112 (15) ◽  
pp. 4546-4551 ◽  
Author(s):  
Angel Martinez ◽  
Leonardo Hermosillo ◽  
Mykola Tasinkevych ◽  
Ivan I. Smalyukh
Keyword(s):  
Boundary Conditions ◽  
Self Assembly ◽  
Structural Organization ◽  
Building Blocks ◽  
Elastic Coupling ◽  
Defect Structures ◽  
Two Photon ◽  
Colloidal Properties ◽  
And Topology ◽  
Orientational Ordering

Geometric shape and topology of constituent particles can alter many colloidal properties such as Brownian motion, self-assembly, and phase behavior. Thus far, only single-component building blocks of colloids with connected surfaces have been studied, although topological colloids, with constituent particles shaped as freestanding knots and handlebodies of different genus, have been recently introduced. Here we develop a topological class of colloids shaped as multicomponent links. Using two-photon photopolymerization, we fabricate colloidal microparticle analogs of the classic examples of links studied in the field of topology, the Hopf and Solomon links, which we disperse in nematic fluids that possess orientational ordering of anisotropic rod-like molecules. The surfaces of these particles are treated to impose tangential or perpendicular boundary conditions for the alignment of liquid crystal molecules, so that they generate a host of topologically nontrivial field and defect structures in the dispersing nematic medium, resulting in an elastic coupling between the linked constituents. The interplay between the topologies of surfaces of linked colloids and the molecular alignment field of the nematic host reveals that linking of particle rings with perpendicular boundary conditions is commonly accompanied by linking of closed singular defect loops, laying the foundations for fabricating complex composite materials with interlinking-based structural organization.

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