The Experts below are selected from a list of 3765 Experts worldwide ranked by ideXlab platform
Helen F. Gleeson - One of the best experts on this subject based on the ideXlab platform.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.
Nature communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
Nature Communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxeticity in synthetic materials is realised by geometrical design of porous structures rather than on a molecular level. Here the authors demonstrate auxeticity in a non-porous liquid crystal elastomer overcoming Porosity related weakening of the material and opening a pathway to designed molecular auxetic materials. Auxetic materials have negative Poisson’s ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics – non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson’s ratio measured to date being -0.74 ± 0.03 – larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, Q _B = -0.41 ± 0.01 – further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
arXiv: Soft Condensed Matter, 2018Co-Authors: Devesh Mistry, Simon D. Connell, Philip B. Morgan, John H. Clamp, Stuart L Micklethwaite, Helen F. GleesonAbstract:"Auxetic" materials have the counter-intuitive property of expanding rather than contracting perpendicular to an applied stretch, formally they have negative Poisson's Ratios (PRs).[1,2] This results in properties such as enhanced energy absorption and indentation resistance, which means that auxetics have potential for applications in areas from aerospace to biomedical industries.[3,4] Existing synthetic auxetics are all created by carefully structuring porous geometries from positive PR materials. Crucially, their geometry causes the auxeticity.[3,4] The necessary Porosity weakens the material compared to the bulk and the structure must be engineered, for example, by using resource-intensive additive manufacturing processes.[1,5] A longstanding goal for researchers has been the development of a synthetic material that has intrinsic auxetic behaviour. Such "molecular auxetics" would Avoid Porosity-weakening and their very existence implies chemical tuneability.[1,4-9] However molecular auxeticity has never previously been proven for a synthetic material.[6,7] Here we present a synthetic molecular auxetic based on a monodomain liquid crystal elastomer (LCE). When stressed perpendicular to the alignment direction, the LCE becomes auxetic at strains greater than approximately 0.8 with a minimum PR of -0.8. The critical strain for auxeticity coincides with the occurrence of a negative liquid crystal order parameter (LCOP). We show the auxeticity agrees with theoretical predictions derived from the Warner and Terentjev theory of LCEs.[10] This demonstration of a synthetic molecular auxetic represents the origin of a new approach to producing molecular auxetics with a range of physical properties and functional behaviours. Further, it demonstrates a novel feature of LCEs and a route for realisation of the molecular auxetic technologies that have been proposed over the years.
Devesh Mistry - One of the best experts on this subject based on the ideXlab platform.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.
Nature communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
Nature Communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxeticity in synthetic materials is realised by geometrical design of porous structures rather than on a molecular level. Here the authors demonstrate auxeticity in a non-porous liquid crystal elastomer overcoming Porosity related weakening of the material and opening a pathway to designed molecular auxetic materials. Auxetic materials have negative Poisson’s ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics – non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson’s ratio measured to date being -0.74 ± 0.03 – larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, Q _B = -0.41 ± 0.01 – further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
arXiv: Soft Condensed Matter, 2018Co-Authors: Devesh Mistry, Simon D. Connell, Philip B. Morgan, John H. Clamp, Stuart L Micklethwaite, Helen F. GleesonAbstract:"Auxetic" materials have the counter-intuitive property of expanding rather than contracting perpendicular to an applied stretch, formally they have negative Poisson's Ratios (PRs).[1,2] This results in properties such as enhanced energy absorption and indentation resistance, which means that auxetics have potential for applications in areas from aerospace to biomedical industries.[3,4] Existing synthetic auxetics are all created by carefully structuring porous geometries from positive PR materials. Crucially, their geometry causes the auxeticity.[3,4] The necessary Porosity weakens the material compared to the bulk and the structure must be engineered, for example, by using resource-intensive additive manufacturing processes.[1,5] A longstanding goal for researchers has been the development of a synthetic material that has intrinsic auxetic behaviour. Such "molecular auxetics" would Avoid Porosity-weakening and their very existence implies chemical tuneability.[1,4-9] However molecular auxeticity has never previously been proven for a synthetic material.[6,7] Here we present a synthetic molecular auxetic based on a monodomain liquid crystal elastomer (LCE). When stressed perpendicular to the alignment direction, the LCE becomes auxetic at strains greater than approximately 0.8 with a minimum PR of -0.8. The critical strain for auxeticity coincides with the occurrence of a negative liquid crystal order parameter (LCOP). We show the auxeticity agrees with theoretical predictions derived from the Warner and Terentjev theory of LCEs.[10] This demonstration of a synthetic molecular auxetic represents the origin of a new approach to producing molecular auxetics with a range of physical properties and functional behaviours. Further, it demonstrates a novel feature of LCEs and a route for realisation of the molecular auxetic technologies that have been proposed over the years.
Simon D. Connell - One of the best experts on this subject based on the ideXlab platform.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.
Nature communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
Nature Communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxeticity in synthetic materials is realised by geometrical design of porous structures rather than on a molecular level. Here the authors demonstrate auxeticity in a non-porous liquid crystal elastomer overcoming Porosity related weakening of the material and opening a pathway to designed molecular auxetic materials. Auxetic materials have negative Poisson’s ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics – non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson’s ratio measured to date being -0.74 ± 0.03 – larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, Q _B = -0.41 ± 0.01 – further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
arXiv: Soft Condensed Matter, 2018Co-Authors: Devesh Mistry, Simon D. Connell, Philip B. Morgan, John H. Clamp, Stuart L Micklethwaite, Helen F. GleesonAbstract:"Auxetic" materials have the counter-intuitive property of expanding rather than contracting perpendicular to an applied stretch, formally they have negative Poisson's Ratios (PRs).[1,2] This results in properties such as enhanced energy absorption and indentation resistance, which means that auxetics have potential for applications in areas from aerospace to biomedical industries.[3,4] Existing synthetic auxetics are all created by carefully structuring porous geometries from positive PR materials. Crucially, their geometry causes the auxeticity.[3,4] The necessary Porosity weakens the material compared to the bulk and the structure must be engineered, for example, by using resource-intensive additive manufacturing processes.[1,5] A longstanding goal for researchers has been the development of a synthetic material that has intrinsic auxetic behaviour. Such "molecular auxetics" would Avoid Porosity-weakening and their very existence implies chemical tuneability.[1,4-9] However molecular auxeticity has never previously been proven for a synthetic material.[6,7] Here we present a synthetic molecular auxetic based on a monodomain liquid crystal elastomer (LCE). When stressed perpendicular to the alignment direction, the LCE becomes auxetic at strains greater than approximately 0.8 with a minimum PR of -0.8. The critical strain for auxeticity coincides with the occurrence of a negative liquid crystal order parameter (LCOP). We show the auxeticity agrees with theoretical predictions derived from the Warner and Terentjev theory of LCEs.[10] This demonstration of a synthetic molecular auxetic represents the origin of a new approach to producing molecular auxetics with a range of physical properties and functional behaviours. Further, it demonstrates a novel feature of LCEs and a route for realisation of the molecular auxetic technologies that have been proposed over the years.
Philip B. Morgan - One of the best experts on this subject based on the ideXlab platform.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.
Nature communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
Nature Communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxeticity in synthetic materials is realised by geometrical design of porous structures rather than on a molecular level. Here the authors demonstrate auxeticity in a non-porous liquid crystal elastomer overcoming Porosity related weakening of the material and opening a pathway to designed molecular auxetic materials. Auxetic materials have negative Poisson’s ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics – non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson’s ratio measured to date being -0.74 ± 0.03 – larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, Q _B = -0.41 ± 0.01 – further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
arXiv: Soft Condensed Matter, 2018Co-Authors: Devesh Mistry, Simon D. Connell, Philip B. Morgan, John H. Clamp, Stuart L Micklethwaite, Helen F. GleesonAbstract:"Auxetic" materials have the counter-intuitive property of expanding rather than contracting perpendicular to an applied stretch, formally they have negative Poisson's Ratios (PRs).[1,2] This results in properties such as enhanced energy absorption and indentation resistance, which means that auxetics have potential for applications in areas from aerospace to biomedical industries.[3,4] Existing synthetic auxetics are all created by carefully structuring porous geometries from positive PR materials. Crucially, their geometry causes the auxeticity.[3,4] The necessary Porosity weakens the material compared to the bulk and the structure must be engineered, for example, by using resource-intensive additive manufacturing processes.[1,5] A longstanding goal for researchers has been the development of a synthetic material that has intrinsic auxetic behaviour. Such "molecular auxetics" would Avoid Porosity-weakening and their very existence implies chemical tuneability.[1,4-9] However molecular auxeticity has never previously been proven for a synthetic material.[6,7] Here we present a synthetic molecular auxetic based on a monodomain liquid crystal elastomer (LCE). When stressed perpendicular to the alignment direction, the LCE becomes auxetic at strains greater than approximately 0.8 with a minimum PR of -0.8. The critical strain for auxeticity coincides with the occurrence of a negative liquid crystal order parameter (LCOP). We show the auxeticity agrees with theoretical predictions derived from the Warner and Terentjev theory of LCEs.[10] This demonstration of a synthetic molecular auxetic represents the origin of a new approach to producing molecular auxetics with a range of physical properties and functional behaviours. Further, it demonstrates a novel feature of LCEs and a route for realisation of the molecular auxetic technologies that have been proposed over the years.
John H. Clamp - One of the best experts on this subject based on the ideXlab platform.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.
Nature communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
Nature Communications, 2018Co-Authors: Devesh Mistry, Simon D. Connell, S L Mickthwaite, Philip B. Morgan, John H. Clamp, Helen F. GleesonAbstract:Auxeticity in synthetic materials is realised by geometrical design of porous structures rather than on a molecular level. Here the authors demonstrate auxeticity in a non-porous liquid crystal elastomer overcoming Porosity related weakening of the material and opening a pathway to designed molecular auxetic materials. Auxetic materials have negative Poisson’s ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics – non-porous, inherently auxetic materials which are simple to fabricate and Avoid Porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson’s ratio measured to date being -0.74 ± 0.03 – larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, Q _B = -0.41 ± 0.01 – further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.
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coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer
arXiv: Soft Condensed Matter, 2018Co-Authors: Devesh Mistry, Simon D. Connell, Philip B. Morgan, John H. Clamp, Stuart L Micklethwaite, Helen F. GleesonAbstract:"Auxetic" materials have the counter-intuitive property of expanding rather than contracting perpendicular to an applied stretch, formally they have negative Poisson's Ratios (PRs).[1,2] This results in properties such as enhanced energy absorption and indentation resistance, which means that auxetics have potential for applications in areas from aerospace to biomedical industries.[3,4] Existing synthetic auxetics are all created by carefully structuring porous geometries from positive PR materials. Crucially, their geometry causes the auxeticity.[3,4] The necessary Porosity weakens the material compared to the bulk and the structure must be engineered, for example, by using resource-intensive additive manufacturing processes.[1,5] A longstanding goal for researchers has been the development of a synthetic material that has intrinsic auxetic behaviour. Such "molecular auxetics" would Avoid Porosity-weakening and their very existence implies chemical tuneability.[1,4-9] However molecular auxeticity has never previously been proven for a synthetic material.[6,7] Here we present a synthetic molecular auxetic based on a monodomain liquid crystal elastomer (LCE). When stressed perpendicular to the alignment direction, the LCE becomes auxetic at strains greater than approximately 0.8 with a minimum PR of -0.8. The critical strain for auxeticity coincides with the occurrence of a negative liquid crystal order parameter (LCOP). We show the auxeticity agrees with theoretical predictions derived from the Warner and Terentjev theory of LCEs.[10] This demonstration of a synthetic molecular auxetic represents the origin of a new approach to producing molecular auxetics with a range of physical properties and functional behaviours. Further, it demonstrates a novel feature of LCEs and a route for realisation of the molecular auxetic technologies that have been proposed over the years.
