Silicone-Based Adhesives with Highly Tunable Adhesion Force for Skin-Contact Applications.

A fundamental approach to fabricating silicone-based adhesives with highly tunable adhesion force for the skin-contact applications is presented. Liquid blends consisting of vinyl-multifunctional polydimethylsiloxane (V-PDMS), hydride-terminated PDMS (H-PDMS), and a tackifier composed of a silanol-terminated PDMS/MQ resin mixture and the MQ resin are used as the adhesive materials. The peel adhesion force of addition-cured adhesives on the skin is increased by increasing the H-PDMS molecular weights and the tackifier content, and decreasing the H-PDMS/V-PDMS ratio.

Attogram mass sensing based on silicon microbeam resonators.

Using doubly-clamped silicon (Si) microbeam resonators, we demonstrate sub-attogram per Hertz (ag/Hz) mass sensitivity, which is extremely high sensitivity achieved by micro-scale MEMS mass sensors. We also characterize unusual buckling phenomena of the resonators. The thin-film based resonator is composed of a Si microbeam surrounded by silicon nitride (SiN) anchors, which significantly improve performance by providing fixation on the microbeam and stabilizing oscillating motion.

Integrated Flexible Electronic Devices Based on Passive Alignment for Physiological Measurement.

This study proposes a simple method of fabricating flexible electronic devices using a metal template for passive alignment between chip components and an interconnect layer, which enabled efficient alignment with high accuracy. An electrocardiogram (ECG) sensor was fabricated using 20 µm thick polyimide (PI) film as a flexible substrate to demonstrate the feasibility of the proposed method. The interconnect layer was fabricated by a two-step photolithography process and evaporation.

Flexible Nonstick Replica Mold for Transfer Printing of Ag Ink.

We report the fabrication of flexible replica molds for transfer printing of Ag ink on a rigid glass substrate. As mold precursors, acrylic mixtures were prepared from silsesquioxane-based materials, silicone acrylate, poly(propylene glycol) diacrylate, 3,3,4,4,5,5,6,6,7,7,8,8, 9,9,10,10,10-heptadecafluorodecyl methacrylate, and photoinitiator. By using these materials, the replica molds were fabricated from a silicon master onto a flexible substrate by means of UV-assisted molding process at room temperature.

Flexion bonding transfer of multilayered graphene as a top electrode in transparent organic light-emitting diodes.

Graphene has attracted considerable attention as a next-generation transparent conducting electrode, because of its high electrical conductivity and optical transparency. Various optoelectronic devices comprising graphene as a bottom electrode, such as organic light-emitting diodes (OLEDs), organic photovoltaics, quantum-dot LEDs, and light-emitting electrochemical cells, have recently been reported. However, performance of optoelectronic devices using graphene as top electrodes is limited, because the lamination process through which graphene is positioned as the top layer of these conventional OLEDs is a lack of control in the surface roughness, the gapless contact, and the flexion bonding between graphene and organic layer of the device.

Fabrication of Large-Area Hierarchical Structure Array Using Siliconized-Silsesquioxane as a Nanoscale Etching Barrier.

A material approach to fabricate a large-area hierarchical structure array is presented. The replica molding and oxygen (O2) plasma etching processes were combined to fabricate a large-area hierarchical structure array. Liquid blends consisting of siliconized silsesquioxane acrylate (Si-SSQA), ethylene glycol dimethacrylate (EGDMA), and photoinitiator are developed as a roughness amplifying material during O2 plasma etching.

Application of thermal initiator for characteristic improvements of polymeric replica mold for UV nanoimprint lithography.

We report the improvement of the hardness and modulus properties in a silsesquioxane-based soft replica mold by adding thermal initiator, without deteriorating the UV transmittance at the wavelength of 365 nm. It is found that thermal initiator used for this work contributes to improving the hardness and modulus values up to 0.175 and 3.

Direct nanopatterning of silsesquioxane/poly(ethylene glycol) blends with high stability and nonfouling properties.

A free-radical-polymerizable SSQ/PEG blend with direct patternability has been proposed as an ideal nonfouling material for nanostructure-based biomedical applications. Cured SSQ/PEG networks show an UV transparency of >90% at 365 nm, high resistance to organic/aqueous solutions, hydrophilicity and Young's moduli of 1.898-2.

Photocurable silsesquioxane-based formulations as versatile resins for nanoimprint lithography.

Methacrylate octafunctionalized silsesquioxane (SSQMA) was shown to be an ideal material with high performance for ultraviolet (UV)-based nanoimprint lithography (NIL). The total viscosity of SSQMA-based formulations was adjusted to between 0.8 and 50 cP by incorporating low-viscosity acrylic additives, making the formulations suitable for UV-based NIL.

Direct fabrication of integrated 3D Au nanobox arrays by sidewall deposition with controllable heights and thicknesses.

This paper provides a unique strategy for controlling integrated hollow nanostructure arrays such as boxes or pillars at the nanometer scale. The key merit of this technique is that it can overcome resolution limits by sidewall deposition and deposit various materials using a sputtering method. The sputtering method can be replaced by other dry deposition techniques such as pulsed laser deposition (PLD) for complex functional materials.

Replica mold for nanoimprint lithography from a novel hybrid resin.

The use of durable replica molds with high feature resolution has been proposed as an inexpensive and convenient route for manufacturing nanostructured materials. A simple and fast duplication method, involving the use of a master mold to create durable polymer replicas as imprinting molds, has been demonstrated using both UV- and thermal nanoimprinting lithography (NIL). To obtain a high-durability replicating material, a dual UV/thermal-curable, organic-inorganic hybrid resin was synthesized using a sol-gel-based combinatorial method.

Nanoarrays of tethered lipid bilayer rafts on poly(vinyl alcohol) hydrogels.

Lipid rafts are cholesterol- and sphingolipid-rich domains that function as platforms for signal transduction and other cellular processes. Tethered lipid bilayers have been proposed as a promising model to describe the structure and function of cell membranes. We report a nano(submicro) array of tethered lipid bilayer raft membranes (tLBRMs) comprising a biosensing platform.

Single probe nucleic acid immobilization on chemically modified single protein by controlling ionic strength and pH.

In an effort toward determining the feasibility of single molecule analysis, we describe a case whereby the binding of one biotinylated DNA to one streptavidin molecule via electrostatic interactions was controlled by altering in pH 4.0-9.0 and 0.

Facile and rapid direct gold surface immobilization with controlled orientation for carbohydrates.

Effective surface immobilization is a prerequisite for numerous carbohydrate-related studies including carbohydrate-biomolecule interactions. In the present work, we report a simple and rapid modification technique for diverse carbohydrate types in which direct oriented immobilization onto a gold surface is accomplished by coupling the amine group of a thiol group-bearing aminophenyl disulfide as a new coupling reagent with an aldehyde group of the terminal reducing sugar in the carbohydrate. To demonstrate the generality of this proposed reductive amination method, we examined its use for three types of carbohydrates: glucose (monosaccharide), lactose (disaccharide), and GM1 pentasaccharide.

A novel route for immobilization of oligonucleotides onto modified silica nanoparticles.

A novel approach for immobilization of probe oligonucleotides that uses zirconium phosphate modified silica nanoparticles is proposed. The surface modification of nanoparticles was carried out in two stages. Initially binding of Zr4+ to the surface of silica nanoparticles and later treated with phosphoric acid for terminal phosphate groups.