#block copolymers

Machine learning teaches membranes to sort by chemical affinity

Ultrafiltration membranes used in pharmaceutical manufacturing and other industrial processes have long relied on separating molecules by size. Now, Cornell researchers have created porous materials that filter molecules by their chemical makeup. Two molecules of identical size and weight but different chemistry, such as antibodies with distinct molecular structure, are difficult to separate using current ultrafiltration (UF) membrane technology. But in a study published in Nature Communications, researchers find that blending chemically distinct block copolymer micelles—tiny self-assembling polymer spheres—could be applied to making membranes capable of filtering molecules by chemical affinity. "This is the first real pathway to creating UF membranes with chemically diverse pore surfaces," said Ulrich Wiesner, the Spencer T. Olin Professor of Materials Science and Engineering, and the study's senior author. "In principle, post-fabrication processes may achieve this, but the cost would be prohibitive for industry to adopt it. This new approach could truly revolutionize ultrafiltration."

A quick stretch switches this polymer's capacity to transport heat

Most materials have an inherent capacity to handle heat. Plastic, for instance, is typically a poor thermal conductor, whereas materials like marble move heat more efficiently. If you were to place one hand on a marble countertop and the other on a plastic cutting board, the marble would conduct more heat away from your hand, creating a colder sensation compared to the plastic. Typically, a material's thermal conductivity cannot be changed without remanufacturing it. But MIT engineers have now found that a relatively common material can switch its thermal conductivity. Simply stretching the material quickly dials up its heat conductance, from a baseline similar to that of plastic to a higher capacity closer to that of marble. When the material springs back to its unstretched form, it returns to its plastic-like properties.

3D-printed superconductor achieves record performance with soft matter approach

Nearly a decade after they first demonstrated that soft materials could guide the formation of superconductors, Cornell researchers have achieved a one-step, 3D printing method that produces superconductors with record properties. The advance, detailed in Nature Communications, builds on years of interdisciplinary work led by Ulrich Wiesner, the Spencer T. Olin Professor in the Department of Materials Science and Engineering, and could improve technologies such as superconducting magnets and quantum devices. Wiesner and colleagues reported in 2016 the first self-assembled superconductor using block copolymers—soft, chain-like molecules that naturally arrange themselves into orderly, repeating nanoscale structures. By 2021, the group found that these soft material approaches could produce superconducting properties on par with conventional methods.

Algorithm offers unprecedented insight into copolymer block-length distributions

Analytical chemistry researchers at the University of Amsterdam's Van 't Hoff Institute for Molecular Sciences (HIMS) have developed a novel algorithm that significantly improves the analysis of copolymers. It allows the determination of their block structure, which has until now been impossible using common analytical approaches. The researchers present their achievement in two recent papers in Macromolecules and Analytica Chimica Acta. The research was conducted within the public-private PARADISE consortium. It aims to better understand the hidden complexities of polymer materials and open the door to a new generation of smart, sustainable polymers by bringing advanced data analysis into the heart of materials science. The consortium consists of academic researchers at Vrije Universiteit Amsterdam (VU) and the University of Amsterdam (UvA) with experts from industrial partners Covestro, DSM, Shell, and Genentech.

Transparent stretchable substrate without image distortion shows potential for next-generation displays

Stretchable display materials, which are gaining traction in the next-generation display market, have the advantage of being able to stretch and bend freely, but the limitations of existing materials have resulted in distorted screens and poor fit. General elastomeric substrates are prone to screen distortion due to the "Poisson's ratio" phenomenon, in which stretching in one direction causes the screen to shrink in the vertical direction. In particular, electronics that are in close contact with the skin, such as wearable devices, are at risk of wrinkling or pulling on the skin during stretching and shrinking, resulting in poor fit and performance. A research team led by Dr. Jeong Gon Son of the Korea Institute of Science and Technology (KIST) and Professor Yongtaek Hong of Seoul National University have developed a nanostructure-aligned stretchable substrate that dramatically lowers the Poisson's ratio. The work is published in the journal Advanced Materials.

Stretchable, flexible, recyclable: 3D printing method creates fantastic plastic

Princeton engineers have developed an easily scalable 3D printing technique to manufacture soft plastics with programmed stretchiness and flexibility that are also recyclable and inexpensive—qualities not typically combined in commercially manufactured materials. In an article in the journal Advanced Functional Materials, a team led by Emily Davidson reported that they used a class of widely available polymers called thermoplastic elastomers to create soft 3D printed structures with tunable stiffness. Engineers can design the print path used by the 3D printer to program the plastic's physical properties so that a device can stretch and flex repeatedly in one direction while remaining rigid in another. Davidson, an assistant professor of chemical and biological engineering, said this approach to engineering soft architected materials could have many uses, such as soft robots, medical devices and prosthetics, strong lightweight helmets, and custom high-performance shoe soles.

Advances in semiconductor patterning: New block copolymer achieves 7.6 nm line width

A recently developed block copolymer could help push the limits of integration and miniaturization in semiconductor manufacturing, report scientists at Tokyo Institute of Technology (Tokyo Tech) and Tokyo Ohka Kogyo (TOK). Chemically tailored for reliable directed self-assembly, the proposed compound can arrange itself into perpendicular lamellar structures whose half-pitch width is less than 10 nanometers, outperforming conventional and widely used block copolymers. Miniaturization is one of the fundamental qualities of modern electronics and is largely responsible for the incredible increments in performance witnessed over the past decades. To keep this momentum going, it is necessary to achieve circuit patterns finer than the existing ones on semiconductor chips, which are a crucial part of all electronic devices. Some experts estimate that, by 2037, the smallest distance between features in semiconductor devices, known as "half-pitch," will need to be as small as 8 nm to support next-generation electronics, emphasizing the need for advancements in lithographic processes (method of creating highly complex circuit patterns on semiconductor parts).

A recently developed block copolymer could help push the limits of integration and miniaturization in semiconductor manufacturing, report scientists in Tokyo Tech and TOK. Chemically tailored for reliable directed self-assembly, the proposed compound can arrange itself into perpendicular lamellar structures whose half-pitch width is less than 10 nanometers, outperforming conventional and widely used block copolymers. Miniaturization is one of the fundamental qualities of modern electronics and is largely responsible for the incredible increments in performance witnessed over the past decades. To keep this momentum going, it is necessary to achieve circuit patterns finer than the existing ones on semiconductor chips, which are a crucial part of all electronic devices. Some experts estimate that, by 2037, the smallest distance between features in semiconductor devices, known as 'half-pitch,' will need to be as small as 8 nm to support next-generation electronics, emphasizing the need for advancements in lithographic processes (method of creating highly complex circuit patterns on semiconductor parts).