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(a) A schematic diagram of the surface of an axisymmetric tip, which has a conical portion with cone angle θ, and a spherical portion with tip radius Rtip and tip angle θtip; (b) a schematic diagram of the contact with contact radius Rcontact
Source publication
A mechanics model is developed for the contact radius of stamps with pyramid tips in transfer printing. This is important to the realization of reversible control of adhesion, which has many important applications, such as climbing robots, medical tapes, and transfer printing of electronics. The contact radius is shown to scale linearly with the wo...
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Citations
... At micro-and nanoscales, adhesion between bodies may become very important and should be taken into consideration to better characterize the associated material responses [49]. The effect of adhesion is particularly remarkable in soft viscoelastic materials [50][51][52]. Adhesive contact analysis of piezoelectric materials was first carried out by Chen and Yu [53]. When applying Fabrikant's results, we find that an exact expression of any field variable at an arbitrary point in the half-space may also be obtained. ...
Significant progress has been made in mixed boundary-value problems associated with three-dimensional (3D) crack and contact analyses of advanced materials featuring more complexities compared to the conventional isotropic elastic materials. These include material anisotropy and multifield coupling, two typical characteristics of most current multifunctional materials. In this paper we try to present a state-of-the-art description of 3D exact/analytical solutions derived for crack and contact problems of elastic solids with both transverse isotropy and multifield coupling in the latest decade by the potential theory method in the spirit of V. I. Fabrikant, whose ingenious breakthrough brings new vigor and vitality to the old research subject of classical potential theory. We are particularly interested in crack and contact problems with certain nonlinear features. Emphasis is also placed on the coupling between the temperature field (or the like) and other physical fields (e.g., elastic, electric, and magnetic fields). We further highlight the practical significance of 3D contact solutions, in particular in applications related to modern scanning probe microscopes. © 2015, The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.
... Upon release of pre-stretch in the substrate the inorganic thin films buckle to yield their stretchability. Several strategies for transfer printing, and the corresponding mechanics models, have been developed [14], such as 1) kinetically-controlled transfer printing [15][16][17]: The inorganic electronic materials are retracted rapidly by an elastomeric stamp, and printed slowly to make use of the high and low adhesion strengths respectively at large and small peeling rates due to viscoelasticity of the stamp; 2) surface-relief-assisted transfer printing [18][19][20][21][22]: The inorganic electronic materials are retracted by an elastomeric stamp with the surface relief structures, such as microtips, to achieve large surface contact with the inorganic materials (and therefore large adhesion force) during retraction, and small contact area during printing; 3) shear-enhanced transfer printing [23,24]: Shear loading protocols are adopted to mechanically initiates separation at the adhesive surface via directional shearing at the interface to control the printing of inorganic materials; 4) laser-driven transfer printing [25][26][27]: During printing a laser pulse initiates separation at the adhesive surface due to large thermal mismatch between the stamp and inorganic materials; and 5) Active-pressure-control-assisted transfer printing [28]: Surface adhesion is modulated by pressurizing microchannels under a thin layer of membrane in a controlled manner to induce a variety level of surface deformation via inflation in printing. Mechanics models have also been developed to establish the criterion for stamp collapse in transfer printing [29][30][31]. ...
Recent advances in mechanics and materials provide routes to integrated circuits that offer the electrical properties of conventional, rigid wafer-based technologies but with the ability to be stretched, compressed, twisted, bent and deformed into arbitrary, curvilinear shapes. This paper summarizes developments in this emerging field, with descriptions of application opportunities, fundamental aspects, representative devices, and particularly the effect of plastic deformation.
... 45,69,[71][72][73][74] An important consideration is in control over the adhesion between nanomaterials and the surfaces of the stamps, in ways that allow switching from strong to weak states for retrieval and printing, respectively. 69,70,75,76 Various approaches, ranging from those that exploit viscoelastic effects 69,75 to interface shear loading 76 to pressureinduced contact modulation, 70,77 can be effective. In many cases, separate adhesive layers on the receiving substrate can further facilitate the printing. ...
Rapid advances in semiconductor nanomaterials, techniques for their assembly, and strategies for incorporation into functional systems now enable sophisticated modes of functionality and corresponding use scenarios in electronics that cannot be addressed with conventional, wafer-based technologies. This short review highlights enabling developments in the synthesis of one- and two-dimensional semiconductor nanomaterials (that is, NWs and nanomembranes), their manipulation and use in various device components together with concepts in mechanics that allow integration onto flexible plastic foils and stretchable rubber sheets. Examples of systems that combine with or are inspired by biology illustrate the current state-of-the-art in this fast-moving field.
Transfer printing that enables the heterogeneous integration of a variety of materials in desired 2D or 3D layouts is essential for developing existing and envisioned systems such as flexible electronics, stretchable electronics, and micro LED displays. Here, a simple yet robust magnetically driven non‐contact transfer printing technique based on a bi‐stable elastomeric stamp is reported. This stamp features adhesive blocks, a magnetic‐response film with a buckled configuration and a cavity. The magnetic‐response film can be controlled with a rapid snap‐through under a magnetic field to switch interfacial adhesion from strong state for reliable pick‐up to weak state for easy printing, which allows the printing of inks onto arbitrary receivers. Experimental, numerical, and theoretical studies reveal the fundamental aspects of design and operation of the stamp to enable a highly efficient non‐contract transfer printing technique. Demonstrations of this concept in transfer printing of Si platelets, papers, pearl cottons, glass slides, and porous acrylic plates onto various challenging non‐adhesive receivers (e.g., cleanroom wiper, cloth, leather, glass, or paper) illustrate its robust capabilities in manipulation of objects with a wide range of materials and its great potential for deterministic assembly, thereby creating engineering opportunities in applications requiring the heterogeneous integration of diverse materials.
In recent years, important progress has been made in developing design strategies, materials, and associated assembly techniques that provide empowering approaches to electronics with unconventional formats, ones that allow useful but previously hard to realize attributes of function. Notable examples of the progress made include: light weight, large area, high performance electronics, optics, and photonics electronic and optical systems with curvilinear shapes and capacities for accommodating demanding forms of mechanical flexure new device form factors for use in sensing and imaging the integration of high performance electronics in 3-D with demanding nanometer design rules functional bioresponsive electronics and advanced hybrid materials systems for lighting, energy storage, and photovoltaic energy conversion. In this report we highlight advances that are enabling such promising capabilities in technology - specifically, the fabrication of device elements using high performance inorganic electronic materials joined with printing and transfer methods to effect their integration within functional modules. We emphasize in this review considerations of the design strategies and assembly techniques that, when taken together, circumvent limitations imposed by approaches that integrate circuit elements within compact, rigid, and essentially planar form factor devices, and provide a transformational set of capabilities for high performance flexible/stretchable electronics.
Transfer printing is an important and versatile tool for deterministic assembly and integration of micro/nanomaterials on unusual substrates, with promising applications in fabrication of stretchable and flexible electronics. The shape memory polymers (SMP) with triangular surface relief structures are introduced to achieve large, reversible adhesion, thereby with potential applications in temperature-controlled transfer printing. An analytic model is established, and it identifies two mechanisms to increase the adhesion, 1) transition of contact mode from the triangular to trapezoidal configurations, and 2) explicit enhancement in the contact area. The surface relief structures are optimized to achieve reversible adhesion and transfer printing. The theoretical model and results presented can be exploited as design guidelines for future applications of SMP in reversible adhesion and stretchable electronics.
Transfer printing represents a set of techniques for deterministic assembly of micro-and nanomaterials into spatially organized, functional arrangements with two and three-dimensional layouts. Such processes provide versatile routes not only to test structures and vehicles for scientific studies but also to high-performance, heterogeneously integrated functional systems, including those in flexible electronics, three-dimensional and/or curvilinear optoelectronics, and bio-integrated sensing and therapeutic devices. This article summarizes recent advances in a variety of transfer printing techniques, ranging from the mechanics and materials aspects that govern their operation to engineering features of their use in systems with varying levels of complexity. A concluding section presents perspectives on opportunities for basic and applied research, and on emerging use of these methods in high throughput, industrial-scale manufacturing.
