Morphing Matter
Tagging Codebook
Simplified framework | Version 2.3 | 20 October 2026
Use ten core dimensions to sort the morphing-matter inventory. Organize designs through material, element or unit, and architecture, while keeping stimulus, instability and shape output visible across these levels. Add technical detail only when it helps distinguish cases or prepare a dataset for reuse.
This is a project adaptation of three reviews [1–3], not a universal taxonomy. Shape-morphing metamaterials provides the backbone; responsive-material and flat-soft-matter reviews extend the material vocabulary and mechanical pathways.
The three organizing levels
Level | Question |
|---|---|
Material | What constituent material provides the response or carries the load? |
Element or unit | What identifiable building block deforms, and how? A sheet or ribbon can be an element without being a repeating unit cell. |
Architecture | How are elements, layers or programmed regions arranged and coupled to produce the overall shape? |
The ten core dimensions
Field | Record |
|---|---|
1 Material | Families, composition structure and response |
2 Stimulus | Applied physical input |
3 Element form | Shape or type of the building block |
4 Element motion | How the building block deforms or moves |
5 Architecture | Assembly form, arrangement and compatibility |
6 Instability | Whether instability participates; type and location if known |
7 Shape output | The resulting transformation of the scoped object |
8 Programmability | Where and how the morphing response is encoded |
9 Functional task | What the morphing enables in the scoped application |
10 Preparation and fabrication | How the material and design were physically realized |
Core means complete each field with a supported value or an explicit unknown. It does not mean that every paper must have a unit cell, instability, or an active material. These ten dimensions are independent filters, not mutually exclusive bins.
Assigning the core tags
Choose a specific design or example first. Select all supported values within a field; identify the component when different values describe different parts. Use “Other specified” with a short description if the vocabulary does not fit.
1 Material
Families: LCE or liquid crystal glass; hydrogel; shape-memory polymer; shape-memory alloy; magnetic composite; electroactive polymer; elastomer; wood or cellulose; other polymer; metal; ceramic; other specified.
Add a short response phrase: for example swelling, thermal expansion, nematic contraction, shape-memory recovery, magnetic response, viscoelastic relaxation, or passive elasticity. Keep family and response distinct. Name multiple constituents when they have different roles; a pressure-driven chamber need not contain a stimulus-responsive material.
Composition structure: choose one per named material or design scope: single material; composite; discrete multimaterial; combined composite and discrete multimaterial. A composite combines constituents within a material, such as fibres or particles in a matrix. Discrete multimaterial means distinct joined or patterned material regions. Use the combined value when both occur, for example a composite strip bonded to a separate membrane. Record the constituent families as well; these labels do not replace them.
2 Stimulus
Values: mechanical force or displacement; pressure; temperature; humidity or water exposure; solvent or chemical concentration; pH; electric voltage or current; magnetic field; light; other specified.
Record the applied input. If conversion matters, add a short pathway such as current → heating → contraction. Do not replace an electrical input with “temperature” merely because heating mediates the response. Identify multiple inputs separately.
3 Element form
Values: beam or rod; ribbon; sheet or shell; hinge or crease; panel or plate; tube or chamber; rotating block; spring; other specified.
Name the element: for example a bilayer ribbon, Miura unit, or triangular lattice cell. A compound unit can contain several forms. A numerical mesh element is not a physical unit cell. For a continuum, use its actual sheet, shell or ribbon form.
4 Element motion
Values: extension or contraction; bending; twisting; folding or internal rotation; inflation or volume change; shear; other specified.
Describe deformation at the selected element scale. “Bending” is a motion; “buckling” is an instability and belongs in field 6. A hinge can bend while its adjacent panels rotate. Multiple motion tags are appropriate when both contribute.
Architecture instability and output
5 Architecture
Record three linked descriptors: assembly form, arrangement and compatibility. This retains the assembly logic of [1] while including continuous and layered morphing structures.
Assembly form: single element; continuous patterned body; cellular or network assembly; layered assembly; other specified assembly. Select all that apply to a named scope. Add an interaction note when useful, such as shared joints, bonded layers or a clamped boundary.
Arrangement — select all supported values: periodic (a spatially repeating unit or motif); nonperiodic (no spatially repeating motif); graded (systematic spatial variation in geometry or properties); hierarchical (elements organized into nested structural levels). State whether the tag describes geometry, composition or another property. Hierarchical means structural nesting, not simply that a design has material and architecture levels.
Periodic and nonperiodic are alternatives for the same attribute at the same scale. A periodic geometry may carry a graded or nonperiodic composition pattern; a hierarchical assembly may be periodic at one level and nonperiodic at another. For an isolated element with no meaningful arrangement, record Not applicable.
Compatibility — one value per specified relation and condition: compatible, when neighbouring elements or programmed regions can realize their preferred local deformation modes together; frustrated, when those preferences cannot all be satisfied simultaneously. Identify the parts or fields, stimulus and constraints. A successful final shape does not prove compatibility, and a flat initial state may become frustrated under activation. Use Unknown if unassessed, or Not applicable if no relevant interaction exists.
6 Instability
Choose one status: observed in experiment; predicted in a model only; absent within a tested range; unknown. If experiment and model both support the event, select observed and cite both. Lack of discussion is unknown, not evidence of absence.
If supported, add type: buckling; snap-through; snap-back; wrinkling; creasing; other specified. Add location: within an element; between coupled elements; collective architecture; whole object. Instability may occur at any structural level.
Do not infer bistability from snapping. Stable-state count is an optional refinement that requires common loading, support and environmental conditions. Likewise, buckling can generate useful shape change or limit performance; record the relevant case.
7 Shape output
Values: extension or contraction; bending or curving; coiling or uncoiling; twisting; surface shaping; folding or unfolding; deployment or compaction; discrete shape switching; other specified.
Describe the transformation of the scoped object, preferably as initial → final shape. This differs from field 4: a lattice may use local rotations to achieve global expansion. Use several tags only when each adds information; “surface shaping” can include a specified saddle or dome.
Programmability
8 Where and how morphing is encoded
Link each programmed variable to its target, level and spatial pattern. Complete core entries with a supported value or an explicit unknown.
Field and scope | Allowed values and definition |
|---|---|
Target and level | Name the material region, element or assembly. Choose material, element or architecture; more than one level requires an explanation. Material encodes local response; element encodes component geometry or mechanics; architecture encodes arrangement, connectivity or constraints. |
Programmed variable | Composition; director or fibre orientation; magnetization; stiffness; thickness; crosslink density; residual strain or prestress; crease geometry; cut geometry; channel geometry; cell geometry; connectivity; other specified. Specify what stiffness or orientation refers to. |
Spatial variation | Uniform; in-plane; through-thickness; along-length; volumetric. Name the region and coordinate frame. Uniform cannot coexist with a variation direction for the same variable and scope. Uniform within units and varied across an assembly are separate assignments. |
Pattern representation | Piecewise regions; continuous field; discrete element values; layered profile; image or voxel field; other specified. Choose how the pattern is represented. Link the actual map, coordinate system, resolution or sampling, and units where meaningful. If alternative representations exist, distinguish the linked versions. |
Spatial variation describes where a property varies. Pattern representation describes how that prescription is expressed or stored. A continuous in-plane director field can be stored as an image; its spatial variation and representation are different descriptors.
Compact assignment example
Choice of LCE formulation among struts → architecture → composition → in-plane → discrete element values. Each strut may separately have uniform composition.
The stimulus is what activates the response; the programmed variable is what was prescribed to shape that response. For active control, optionally add a control-program note describing addressing, timing and feedback. Treat the input schedule as a control prescription rather than a material property.
9 Functional task
Many | case | core. Values: shape matching; deployment; locomotion; gripping or manipulation; stiffness modulation; energy absorption or release; fluid transport; electromagnetic reconfiguration; other specified.
Describe what the morphing enables. Shape output records the transformation; functional task records its purpose. For example, bending can support gripping, locomotion or shape matching. Deployment may describe both an unfolding output and a functional task; record each role explicitly.
Use Not applicable for a resource without a task-specific case. Use Unknown when the task of a scoped case is unclear. Mark whether a task is demonstrated, modeled, or proposed by the authors; keep a curator-suggested use explicitly separate. Multiple supported tasks may be assigned.
Preparation and fabrication
10 How the physical design is realized
Many | named material component or assembly | core. Record all supported process tags for the scoped case. These browsing tags describe how a design was made; link the ordered procedure and settings in the metadata record.
Field and scope | Allowed values and definition |
|---|---|
Material preparation | Used as received; mixing or formulation; synthesis or polymerization; composite preparation; biological material treatment; other specified. |
Shaping and assembly | Casting or molding; extrusion; additive manufacturing; cutting or machining; lithography or patterning; folding; lamination or bonding; textile processing; assembly; other specified. |
Programming and postprocessing | Alignment; patterned curing or crosslinking; magnetization; stretching or prestressing; thermal treatment; swelling or solvent conditioning; mechanical training; other specified. |
Assignment rules
Name the material, component or assembly for each tag. A composite strip bonded to a membrane needs separate preparation records for each constituent component and a linked assembly record. Tags do not encode the order of operations.
Programmability records what was prescribed and where; preparation and fabrication records how it was realized. Link each relevant process step to the programmed-variable assignment it establishes. One step can establish several variables, and one variable may require several steps.
Classify a step by its purpose. Heating to cure a polymer is fabrication; heating to establish a programmed state is programming; heating to measure actuation is a test stimulus. Record multiple purposes when supported. Keep experimental loading, sensing and measurement in a separate test protocol.
Use Unknown when the process is not established. Use Not applicable with a reason, for example a purely numerical case with no physical fabrication. Do not assign a proposed fabrication route as though it was performed; distinguish reported, proposed and curator-inferred processes.
Illustrative linked assignment
A printed LCE strut: director orientation along the strut is the programmed variable; alignment during extrusion followed by curing is the preparation route. Link the strut, formulation, print path, curing step and resulting material state. This example is illustrative rather than a newly verified study record.
Optional refinements
Add these only when they resolve a useful distinction. They do not expand the ten-dimension first-pass requirement.
Directional response and internal rotation
Retain anisotropy as an optional response descriptor: material anisotropy, geometric anisotropy, or both, with a stated direction. Internal rotation remains an element-motion tag. The two principles emphasized in [1] are useful lenses, but they are neither equivalent types of information nor exhaustive categories for all morphing matter.
Bending and buckling pathways
Pathway | Assignment rule |
|---|---|
Bending from mismatch | A through-thickness stress or preferred-strain mismatch produces a bending moment and curvature. |
Buckling from compression | In-plane compression destabilizes a flat configuration and produces out-of-plane deformation. |
Combined | Both pathways are supported in the scoped case; state how they interact. |
Other or unresolved | Name another supported route, such as applied-moment bending; otherwise leave the pathway unresolved. |
These pathway tags adapt the flat-soft-matter distinction in [3]. They are especially useful for sheets and ribbons, not a requirement for every design. A curved shape alone cannot identify its pathway. Through-thickness and in-plane patterning also do not, by themselves, prove a specific instability.
Other refinements to add selectively
Stability: monostable (one), bistable (two), or multistable (more than two stable equilibria), with state count and conditions. History: rate, sequence, hysteresis, relaxation, cycling or retained state, only where supported. Feedback: record sensed quantity and controlled input when relevant.
Keep performance measurements and resource readiness outside the browsing tags. Curvature, shape error, speed and repeatability require definitions, units and conditions. Code availability, raw-data access and experimental validation are separate questions.
How to group the inventory
For browsing, start with element form and architecture: sheets, ribbons, folded assemblies, cellular assemblies and chambers. Within a group, filter by material, stimulus, motion, instability or functional task. For mechanism comparisons, regroup across forms using the instability and optional pathway tags. A candidate can appear in more than one group. Preparation and fabrication provides an additional process-based filter across these groups.
These are transparent, tag-based groups. Do not force every candidate into one exclusive family, or treat an unknown as dissimilarity in a later clustering analysis.
Examples worksheet and sources
The examples below are illustrative assignments, not newly verified publication records. They show how similar-looking motions can have different explanations.
Example | Core tag summary |
|---|---|
Swelling bilayer strip | Hydrogel; discrete multimaterial layers; water exposure; ribbon; bending; layered assembly, compatibility unassessed; instability unknown; curving. Programming: composition across thickness, layered profile. Functional task: unspecified in this generic example. |
Rotating-panel lattice | Specify material and composition; mechanical loading; panels and hinges; rotation and hinge bending; cellular assembly, periodic geometry; compatibility and instability require evidence; extension. Programming: cell geometry and connectivity, specify spatial scope and design map. Functional task: unspecified in this generic example. |
One record per scoped example
ID and citation: ____________________ Design or figure: ____________________
Scope and relevant condition: ___________________________________________
1 Families composition response: __________________ 2 Stimulus: __________________
3 Element form: _________________________ 4 Element motion: ____________
5 Form arrangement compatibility: ________ 6 Instability: _________________
7 Shape output: _______________________________________________________
8 Programming target and level: _________________________________________
Variable and spatial variation: ___________________________________________
Pattern representation and map if relevant: ________________________________
9 Functional task and evidence status: ____________________________________
10 Preparation fabrication and procedure link: _____________________________
Evidence note: source and page/figure; which tags are inferred and why.
_____________________________________________________________________
Open question: __________________________ Curator and date: ____________
Use “Unknown—unchecked” or “Unknown—unresolved” where appropriate; use “Not applicable” only with a reason. Keep a source locator for supported assignments. One source note may cover several tags when their support is clear. Review uncertain cases before treating tags as reference labels.
Review foundations
[1] Shape-morphing metamaterials. Nature Reviews Materials (2025). Unit-cell design principles and assembly strategies: source of the unit/architecture backbone and compatibility criteria.
[2] Responsive materials architected in space and time. Xia, Spadaccini and Greer. Nature Reviews Materials (2022). Source of the material-response, stimulus and temporal-programming perspective.
[3] Programming the shape-shifting of flat soft matter. van Manen, Janbaz and Zadpoor. Materials Today 21, 144–163 (2018). Source of the bending-moment versus compression-induced buckling distinction.
Version 2.3 adds preparation and fabrication as dimension 10. This codebook and the ten-dimension framework are embedded in Shape Morphing Data Commons.