{"title":"Folding nano-scale paper cranes–the power of origami and kirigami in metamaterials","authors":"Anna Lappala, N. Macauley","doi":"10.15406/IJBSBE.2018.04.00119","DOIUrl":null,"url":null,"abstract":"Folding, the mechanism of self-assembly into a compact state is universally observed on different scales in a wide range of materials. In this review, we discuss folding and compaction on molecular scales. Generally, folding can be classified into two groups – specific, whereby the number of folding pathways is limited, or non-specific where associations between all functional units are equiprobable, yet directed by a number of physical principles such as coil-globule transition and nucleation processes, regulating the kinetics of collapse as well as the morphology of the final folded state. Complex events such as aggregation, gelation and molecular folding often incorporate both non-specific and specific collapse pathways, linking the two together in a non-trivial manner. Here, we focus on specific ‘designer’ folding pathways of origami and kirigami (a variation of origami that involves cuts) on a molecular scale. These particular folds are a result of highly selective interactions that allow one to robustly produce a large number of stable interaction-dependent collapsed morphologies. Even though the folding of origami relies on trivial operations from a mechanistic perspective, the physics of origami folds is intriguing: origami folds can 1) undergo large reversible deformations 2) show nonlinear auxetic behavior– a property of a material with a negative Poisson’s ratio (i.e. the material expands when tension is applied) 3) bistability (the origami fold has two stable states – expanded and compressed) and 4) topological locking – an increase in resisting force upon folding.1 All the physical properties of origami can be tuned by the geometry of the fold (Figure 1). Like origami, kirigami structures provide multifunctional shape-changing capabilities. Due to an increased number of structural degrees of freedom originating from incisions, kirigami-based 3D nanostructures allow for a larger variety of morphologies as well as load bearing capabilities that are not accessible using traditional origami techniques.2,3","PeriodicalId":15247,"journal":{"name":"Journal of Biosensors and Bioelectronics","volume":"61 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2018-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Biosensors and Bioelectronics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.15406/IJBSBE.2018.04.00119","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1
Abstract
Folding, the mechanism of self-assembly into a compact state is universally observed on different scales in a wide range of materials. In this review, we discuss folding and compaction on molecular scales. Generally, folding can be classified into two groups – specific, whereby the number of folding pathways is limited, or non-specific where associations between all functional units are equiprobable, yet directed by a number of physical principles such as coil-globule transition and nucleation processes, regulating the kinetics of collapse as well as the morphology of the final folded state. Complex events such as aggregation, gelation and molecular folding often incorporate both non-specific and specific collapse pathways, linking the two together in a non-trivial manner. Here, we focus on specific ‘designer’ folding pathways of origami and kirigami (a variation of origami that involves cuts) on a molecular scale. These particular folds are a result of highly selective interactions that allow one to robustly produce a large number of stable interaction-dependent collapsed morphologies. Even though the folding of origami relies on trivial operations from a mechanistic perspective, the physics of origami folds is intriguing: origami folds can 1) undergo large reversible deformations 2) show nonlinear auxetic behavior– a property of a material with a negative Poisson’s ratio (i.e. the material expands when tension is applied) 3) bistability (the origami fold has two stable states – expanded and compressed) and 4) topological locking – an increase in resisting force upon folding.1 All the physical properties of origami can be tuned by the geometry of the fold (Figure 1). Like origami, kirigami structures provide multifunctional shape-changing capabilities. Due to an increased number of structural degrees of freedom originating from incisions, kirigami-based 3D nanostructures allow for a larger variety of morphologies as well as load bearing capabilities that are not accessible using traditional origami techniques.2,3