University of Massachusetts Amherst

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Pressure Sensitive Adhesives
Pressure sensitive adhesives bond two materials when physical pressure is applied to marry the adhesive with the adherent. They are widely applied in self-adhesive tapes, labels and marking films, medical plasters and pads, dermal pharmaceutical dosage forms, medical drapes and biomedical electrodes. Curing current adhesives often involves UV irradiation or heat, capital and energy intensive steps which may produce to toxic byproducts.

 

The invention concerns novel compositions and crosslinking strategies that greatly simplify fabrication of pressure sensitive adhesives.  A soluble and flowable polymer containing latent crosslinking sites is applied to a substrate as a low-viscosity solution or melt.  After application, spontaneous crosslinking occurs at ambient conditions, eliminating the need for post-crosslinking equipment, capital and expense. It also eliminates formation of undesired or toxic residues; allows the formation of crosslinked adhesive layers on temperature-sensitive substrates; enables the use of opaque crosslinkable adhesive formulations; and facilitates the incorporation of adhesives into porous or complex substrates. These strategies may be generalized to broader classes of solvent borne and hot melt pressure adhesives.

 

Published: 8/14/2017   |   Inventor(s): Shelly Peyton, John Klier, Yen Tran, Todd Emrick
Category(s): Engineering, Healthcare, Material science
Fulleropyrrolidine Interlayers for High Efficiency Perovskite Solar Cells
Interface engineering is critical for achieving efficient solar cells.  This invention provides a significant power conversion efficiency (PCE) improvement of fullerene/perovskite planar heterojunction solar cells from 7.50% to 15.48% by inserting a fulleropyrrolidine interlayer between the metal electrode and the electron transport layer. The interlayer enhances recombination resistance, increases electron extraction rate and prolongs free carrier lifetime.cells.
Published: 8/11/2017   |   Inventor(s): Thomas Russell, Todd Emrick, Yao Liu, Zachariah Page
Category(s): Devices, Physical Science, Material science, Clean Energy
Chemically Stable Fibers Electrospun from Polyelectrolytes
The invention is a new platform for fabricating nano- and macro- scale fiber materials and for encapsulation. Complex coacervates are associative complexes of positive and negative polyelectrolytes, which form complexes due to a combination of electrostatic and entropic interactions between the oppositely charged polyions. Due to their aqueous solubility, polyelectrolyte solutions are a good medium for encapsulating small molecules. However, while the concept of polyelectrolyte complexes for a drug delivery system and other applications has seen heightened interest in recent years, significant obstacles and challenges remain both in processing technologies and functionalities of the resulting materials.

 

Electrospinning is an established, versatile, inexpensive and scalable process for creating continuous, nanofibrous mats of non-woven nano-/micro-scale diameter fibers. Electrospun mats hold great promise in biomedical, environmental, and industrial fields.

 

The invention provides novel polymer nanofiber or microfiber mats and methods for their preparation via an aqueous, one-step polyelectrolyte complexation and electrospinning of complex coacervates. The process involves an aqueous medium and no organic solvents and/or strongly acidic or basic condition, resulting in chemically and thermally robust fiber mats. Thus, this process and the resulting materials have tremendous potential as a green processing strategy that can serve as the basis for developing a new class environmentally benign fiber scaffolds for use in applications, such as wound healing, water remediation, catalysis, and food packaging.

 

Published: 8/11/2017   |   Inventor(s): Jessica Schiffman, Sarah Perry, Xiangxi Meng
Category(s): Material science, Healthcare, Engineering
Method OF Transfer Printing
2-dimensional (2D) materials are characterized as being one or two atoms thick. Graphene (image above) is by far the best known 2D material. However, there are many other 2D materials with attractive properties (e.g. hexagonal boron nitrides (hBN), transition metal dichalcogenides, etc.). Due to their superior physical properties, graphene and related 2D materials have the potential to revolutionize many industries, enable development of new devices, and provide new functionalities to existing technologies. In short, these materials have the potential to be disruptive and pervasive. Despite their overwhelming promise, however, industrial scale manufacture of these materials is not yet a reality, due in part to an inability to control layer number and to print over large surface areas.

 

To address this problem, scientists at UMass Amherst have engineered a high-precision printing method that is compatible with current industrial manufacturing processes. This simple method allows single layer 2D material to be patterned, transferred and printed onto a substrate, enabling the fabrication of novel 2D heterostructures devices. Thus, this method will facilitate the assembly of novel devices and enable large-scale manufacture of devices with designed properties.

Published: 8/10/2017   |   Inventor(s): Qiangfei Xia, Peng Lin
Category(s): Material science, Nanotechnology
Patterning of 1-D, 2-D and 3-D Nanostructures
This invention provides methods of manufacturing a nanotextured surface comprising disposing a nanoparticulate ink on a substrate.
Published: 8/9/2017   |   Inventor(s): James Watkins, Rohit Kothari
Category(s): Material science, Nanotechnology, Physical Science, Devices & sensors
Flame Retardant Monomers and Polymers
This invention provides new flame retardant monomers and polymers made using such and other monomers. The new flame retardant monomers can reduce polymer flammability due to char formation. Upon the incorporation of such monomers into the polymer structure, their additional functional groups or handles impart reactivity to the polymer, enabling the formation of new functional polymeric and composite materials.
Published: 9/14/2016   |   Inventor(s): Todd Emrick, Aabid Mir, Umesh Choudhary
Category(s): Chemicals, Material science, Physical Science
Ultra-high Strength Multilayer Graphene Materials
This invention relates to the use of single crystalline graphene to create multilayer structures of graphene materials with superior shear strength.
Published: 9/14/2016   |   Inventor(s): Christos Dimitrakopoulos, Dimitrios Maroudas, Andre Muniz, D. Kurt Gaskill
Category(s): Material science, Nanotechnology, Electronics, Engineering, Physical Science
Method for Preparing Aerogels and Foams
The technology described here is a method for making aerogels, the lightest and lowest density known solid on the planet.  Most aerogels are prepared using supercritical drying or freeze drying.  These techniques use supercritical fluids that are supercritical at high pressures and temperatures and can sometimes be hazardous.  Other supercritical fluid based methods use low pressure solvent removal and/or freezing and both of these methods are energy intensive and result in high production costs.

To prepare aerogels and foam materials using this process, the polymer material is frozen while the remaining steps take place at ambient pressure and room temperature. The resulting bioactive polymer has a bulk density of 500 -2500 grams per cubic meter. Compared to other methods, this is a cost-effective and safe method of preparing foams and aerogels. Moreover, the method consumes less energy and is also environmentally-friendly, as the aqueous solutions and solvents used in the process can be easily recovered and recycled.

Published: 9/13/2016   |   Inventor(s): Kenneth Raymond Carter, Yinyong Li
Category(s): Nanotechnology, Material science, Engineering, Physical Science
Efficient Thermoelectric Converters
The invention provides thermoelectric devices similar to conventional Peltier-elements based on folded, multi-layered nanomembranes prepared from 2-dimensional (2D) van der Waals materials. These van der Waals materials (e.g. graphene, hexagonal boron nitride, and transition metal dichalcogenides) have both single atomic layers with strong in-plane covalent bonding and weak bonding across atomic mononolayers. When devices are fabricated by folding monolayers onto themselves and into layered structures (figure). In this configuration, the electric path is shorter and the thermal path is suppressed. Moreover, multiple elements can be combined in series and parallel configurations to produce a useful amount of electricity. Thus, these devices can be used to convert waste-heat into electricity and can also serve a thermoelectric cooler. Some information about different applications here.
Published: 3/8/2016   |   Inventor(s): Zlatan Aksamija, Robert Blick
Category(s): Clean Energy, Devices, Devices & sensors, Electronics, Engineering, Material science, Nanotechnology, Physical Science
COLORIMETRIC RADIATION SENSORS
Researchers at UMass Amherst have developed sensors for detection of ionizing radiation (e.g. X-ray, gamma ray, and electron beam radiation) based on polymer multilayer films. A radiation sensor includes a substrate and a polymer multilayer film including alternating layers of a high refractive index polymer and a low refractive index polymer that give rise to reflected structural color in the visible region of the spectrum. The high refractive index polymer and the low refractive index polymer each comprise repeat units derived from a photo-crosslinkable monomer. A variety of rigid and flexible substrates can be used to fabricate sensors (for example, Figure 1 shows a multilayer polymer fabricated on a Mylar sheet), and polymer multilayer films can be designed to undergo either a blue or red shift (see Figure 2) in response to ionizing radiation. The radiation sensors are useful in preparing various articles, including wearable patches, packaging materials, labels, and window panes.
Published: 6/19/2015   |   Inventor(s): Ryan Hayward, Maria Chiappelli
Category(s): Healthcare, Devices & sensors, Material science
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