No limit to number of times material can change shape
Although most materials slightly expand when heated, there is a new class of rubber-like material that not only self-stretches upon cooling; it reverts back to its original shape when heated, all without physical manipulation.
The findings were recently published in the journal ACS Macro Letters.
The material is like a shape-memory polymer because it can be switched between two different shapes. “However, unlike other shape-memory polymers, the material does not need to be programmed each cycle—it repeatedly switches shapes, with no external forces, simply upon cooling and heating,” said Mitchell Anthamatten, an associate professor of chemical engineering.
Anthamatten and his team built on the success of a recently developed polymer that can also stretch when cooled. The other polymers need to have small loads—or weights—attached in order to direct the shape to be taken. That is not the case with the Rochester polymer, because Anthamatten’s team “tricked it into thinking” a load was attached.
To carry out their strategy, the researchers introduced permanent stress inside the material. They began with polymer strands that were loosely connected by bonds called crosslinks that create a network of molecules. The material was stretched with a load attached to give it the desired shape. At that point, they added more crosslinks and cooled the polymer, causing crystallization to occur along a preferred direction.
Anthamatten’s team showed that internal crystallization forces are strong enough to stretch the material along one direction. Once cooled below about 50 °C, polymer chain segments pack into highly ordered micro-layers called lamellae. This reorganization occurs within a network of polymer chains, causing the material’s length to increase by over 15 percent.
“The stress we built into the network takes the place of the load and enables the material to ‘remember’ the shape it will assume when it’s later cooled without a load,” said Anthamatten.
Conventional shape-memory polymers need to be reprogrammed after each cycle, but that’s not the case with the material developed by Anthamatten and his team. After multiple cycles of cooling and heating, they found that the material assumed its programmed shape and returned to its initial state with no noticeable deviation.
The Latest on: Shape-memory polymer
via Google News
The Latest on: Shape-memory polymer
- Biomaterial mimicking muscles can turn stem cells into boneon January 18, 2020 at 4:25 pm
According to Professor Andreas Lendlein, author of the paper and head of the HZG's Institute of Biomaterial Science in Teltow, "Our polymer actuator sheet has a so-called shape-memory function. In our ...
- Four-dimensional micro-building blockson January 17, 2020 at 12:24 pm
Researchers have also implemented programmable shape transformations in 2D materials by introducing fibrous micro- and nanoarchitectures (18, 19), reinforcing nanoparticles (20–23), or inhomogeneous ...
- Stem Cells Transformed into Bone Using Artificial Muscle Sheetson January 14, 2020 at 12:34 am
With these synchronised stimuli it is possible to encourage the stem cells to turn themselves into bone cells. "Our polymer actuator sheet has a so-called shape-memory function. In our experiments, ...
- Programming temporal morphing of self-actuated shellson January 13, 2020 at 7:44 pm
Advances in shape-morphing materials, such as hydrogels, shape-memory polymers and light-responsive polymers have enabled prescribing self-directed deformations of initially flat geometries. However, ...
- Artificial muscle sheets transform stem cells into boneon January 13, 2020 at 12:05 pm
To do this, the scientists implemented a so-called shape-memory polymer in stem cell research. The study was published today in the renowned journal, Proceedings of the National Academy of Sciences.
- Global Smart Polymer Market to Boost Business Scope with Key Players BASF SE, Akzo Nobel, DuPont, The Dow Chemical, Evonik Industrieson January 9, 2020 at 12:56 am
Get an extensive research offering detailed information and growth outlook of the Smart Polymer market in the new research report added by Big Market Research. The report presents a brief summary of ...
- Tiny magnetic particles enable new material to bend, twist and grabon December 19, 2019 at 3:27 pm
A team of researchers from the Georgia Institute of Technology and The Ohio State University has developed a material called magnetic shape memory polymer that uses magnetic fields to transform into a ...
- Shape memory polymer developed for gripping heavy objectson December 18, 2019 at 6:54 am
A team of researchers from the Georgia Institute of Technology and The Ohio State University has developed a magnetic shape memory polymer that uses magnetic fields to transform into a variety of ...
- Magnetic fields turn material bendy and twistyon December 17, 2019 at 5:19 am
Magnetic fields can transform a new soft polymer material, called magnetic shape memory polymer, into a variety of shapes. The material could enable a range of new applications from antennas that ...
- New Magnetic Compound Changes Shapes in Response to Magnetic Fieldon December 10, 2019 at 12:25 pm
A team of Georgia Tech and Ohio State University researchers has developed a soft polymer material, called magnetic shape memory polymer, that uses magnetic fields to transform into a variety of ...
via Bing News