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What is Memorysil?

MemorySil = Silly Putty® + Elastomer

In its most basic form, Memorysil is Silly putty® combined with an elastomer. Characteristics of both non-newtonian Silly putty and viscoelastic elastomer combined into one material.  MemorySil is a patented shape-memory silicone rubber developed by physicists at the University of Virginia. It is a "viscoelastic silicone" that temporarily molds to the shape of whatever presses against it, while retaining a permanent default shape to which it very slowly returns when pressure is removed. It feels like a liquid and solid combined. 


MemorySil is a highly engineered polymeric network composed of a polydimethylsiloxane (PDMS) backbone modified with specific chemical crosslinks and plasticizing additives to intentionally introduce high hysteresis and time-dependent mechanical damping. Unlike standard elastic silicones that instantly rebound, viscoelastic silicones exploit specific intermolecular configurations to delay structural recovery after deformation. Shape recovery can take a few seconds or a few hours depending on the formulation. 


The primary structural framework consists of repeating organosilicon units, specifically polyborosiloxanes

Density of crosslinks


  • Low Covalent Crosslink Density: Chains are sparsely joined using functional crosslinkers (such as methylhydrogen siloxane copolymers via platinum-catalyzed hydrosilylation). The long, unlinked segments between these crosslink points preserve fluid-like movement (viscous component).
  • The Elastic Network: The sparse covalent bonds provide the ultimate structural memory. They store potential energy during compression and dictate the material's slow return to its original shape once the stress is removed.
  • Mechanism of damping
  • The characteristic "memory" effect is achieved by manipulating the relationship between the storage modulus (\(G^{\prime }\), representing elasticity) and the loss modulus (\(G^{\prime \prime }\), representing viscosity):
    • Energy Dissipation: When an external force is applied, the long, unjoined siloxane chains slide past one another. The mechanical energy is dissipated as heat via molecular friction rather than being stored like a perfect spring.
    • Hydrogen Bonding Additives: Viscoelastic silicones frequently incorporate non-reactive silicone oils or specific polar additives that form transient hydrogen bonds along the PDMS matrix. These temporary bonds break during compression and slowly reform during relaxation, actively retarding the rate of elastic recovery.

  • Maxwell-Wiechert Model
  • The time-dependent behavior of memory silicone is classically modeled using the Maxwell-Wiechert framework, which represents the material as a parallel network of spring-dashpot elements. The relaxation modulus over time, \(G(t)\), is governed by the equation:
    \(G(t)=G_{e}+\sum _{i=1}^{m}G_{i}e^{-\frac{t}{\tau _{i}}}\)
    Where \(G_{e}\) is the equilibrium elastic modulus, \(G_{i}\) represents the stiffness coefficients of individual polymer segments, and \(\tau _{i}\) represents the discrete relaxation time constants designed into the silicone network to control its slow recovery speed.



    • Silly putty combined with low durometer Elastomer

    MemorySil® is a proprietary, patented viscoelastic silicone elastomer formulated from a specific mixture of base silicone polymers, crosslinking agents, catalysts, and non-reactive plasticizing additives to achieve its dual shape-memory properties. 

    1. The Matrix (Base Polymers)
    The bulk of the material consists of liquid silicone components that establish the physical volume and rubbery texture. [1]
    • Vinyl-Terminated Polydimethylsiloxane (PDMS): The foundational backbone polymer. These are linear chains with reactive vinyl (-CH=CH₂) groups at the ends, which allow them to be linked together during the curing process. [1]
    • Dimethyl Siloxane Copolymers: Short-to-medium chain siloxanes used to adjust the overall starting viscosity of the un-cured liquid mixture.

    2. The Crosslinkers & Network Regulators
    To carefully tune MemorySil so it has low covalent crosslink density (giving it its ultra-soft, fluid-like slow recovery), specific crosslinking molecules are used:
    • Methylhydrogen Siloxane Copolymer: Acts as the bridging molecule. It contains highly reactive silicon-hydrogen (Si-H) bonds that stitch the vinyl-terminated PDMS chains together into a solid 3D network.
    • Siloxane Resin Modifiers: Used in precise proportions to control the matrix's architecture, helping to balance the hard elastic components against the soft flowing components.
    MemorySil does not have a single, fixed durometer because it changes hardness when you lightly touch it, while a standard 10A elastomer stays at one constant hardness.


    Here is the simplest way to understand the difference:



    Standard 10A Elastomer: The Steady Rubber
    • How it feels: Like a soft gummy bear or a gel shoe insert.
    • The durometer: It is fixed at 10A. No matter how long you press it or how many times you squeeze it, it always pushes back with the exact same amount of force. It springs back instantly.

    MemorySil: The Shape-Shifting Silicone
    • How it feels: Like a liquid and a solid combined.
    • The durometer: It starts soft, but as you press it, it temporarily drops to near zero. It yields completely to your finger and slowly oozes out of the way.
    • The recovery: When you let go, it stays squished for a few seconds before slowly crawling back to its original shape. 


    In Summary:
    Think of a standard 10A elastomer like a soft metal spring—it always pushes back hard against you. Think of MemorySil like wet clay that magically remembers to turn back into rubber a few seconds after you stop touching it.
    MemorySil stops a 4 legged table from rocking by acting like a smart, self-adjusting cushion or spring under each leg. adaptive table levelers made of Memorysil completely eliminate the need for manual screws, shims, wobble wedges, or folded paper.

    Memorysil dynamically corrects an uneven floor using its unique physical properties in the following ways:

    1. The Zero-Pressure Effect
    On a regular wobbly table, three legs touch the floor perfectly, while the fourth leg hovers above a low spot. When you install STableLegs made of memorysil, the table's weight pushes down on the three "high" legs. Because MemorySil temporarily yields to zero hardness under stress, those three high legs sink deeply and effortlessly into their silicone pads.

    2. Filling the Low Spot
    As the high legs compress, the table naturally lowers until the fourth, "short" leg finally makes firm contact with the ground. Because the fourth leg isn't carrying the bulk of the table's weight, its MemorySil pad does not compress as much. It stays thicker, automatically filling the gap. 

    3. Absorbing Instant Shocks (No Spring-Back)
    If you lean on the table, a normal rubber pad would compress and immediately push back, creating a bouncy, swaying motion. MemorySil is viscoelastic, meaning it absorbs energy without fighting back. When you apply shifting weights (like resting your elbows or cutting food), the pads absorb the force silently and slowly, leaving the table completely rock-solid and stable.

    4. No Moving Parts
    Traditional automatic levelers rely on springs, hydraulic fluid, or mechanical valves that can jam with dirt or rust over time. Unlike No-rock table and flat tech, MemorySil has zero moving parts—the chemistry of the silicone itself does all the leveling work. It is the only "passive" table leveler that actually works.
    Infusing MemorySil with graphene creates a highly responsive, flexible, shape-recovering touch sensor, whereas Trinity College Dublin’s G-putty acts as a fluid-like, hyper-sensitive impact sensor that physically oozes over time. 
    Both materials rely on the concept of piezoresistivity—where deforming the material breaks a microscopic network of conductive graphene flakes, causing a massive spike in electrical resistance. However, their underlying chemical structures mean they would operate very differently. 


    Mechanical Comparison

    Graphene-Infused MemorySilG-Putty (Trinity College Dublin)
    Base Material
    Cross-linked shape-memory silicone elastomer
    Base Material
    Non-cross-linked silicone polymer (Silly Putty®)
    Physical State
    Solid elastomer (bounces back to a fixed mold)
    Physical State
    Viscous liquid (flows, slumps, and melts into a puddle)
    Shape Memory
    True Elastic Memory. Temporarily yields, but always slowly restores its identical molded geometry.
    Shape Memory
    Fluid Self-Healing. Liquid flow allows the graphene flakes to naturally float back together over time.
    Longevity
    Retains its component shape indefinitely under load.
    Longevity
    Will eventually ooze, migrate, or flatten under continuous pressure.


    How Graphene-Infused MemorySil Would Behave
    Because MemorySil is a true cross-linked elastomer (unlike a raw putty), mixing it with graphene would create a highly structured, smart skin: [1]
    1. The Sensor Mechanism: When you press the material, it deforms. The embedded graphene sheets shift apart, cutting off the electrical pathways and sending a precise "touch" or "pressure" signal to a connected computer. 
    2. Transient Low-Modulus Sensitivity: Because MemorySil temporarily yields to an ultra-low stiffness when pressed, a microscopic touch will deform the material deeply without requiring heavy force. This would make it incredibly sensitive to light touch, while providing a soft, adaptive interface. 
    3. Controlled Electrical Recovery: Once you stop pressing it, MemorySil’s viscoelastic timing takes over. It won't instantly snap back like normal rubber, nor will it permanently deform like raw putty. It will slowly recover its exact original shape over a few seconds, predictably reforming the graphene electrical paths at a controlled, measurable rate.

    Direct Comparison to Trinity College's G-Putty
    Invented by Prof. Jonathan Coleman's team at TCD, G-putty is famous for being so sensitive it can measure a human pulse on the skin or detect a spider's footsteps. 
    • The G-Putty Advantage: Because Silly Putty behaves like a slow fluid, the graphene flakes have exceptionally high mobility. This allows G-putty to achieve a staggering gauge factor (sensitivity rating), making it far more sensitive to microscopic, high-frequency impacts than structured elastomers. 
    • The MemorySil Advantage: G-putty’s biggest limitation is that it behaves like a liquid over long periods. If you put G-putty under a table leg or a continuous weight, it will slowly ooze out sideways and lose its form. Graphene-infused MemorySil would solve this flaw completely. It gives you the soft, high-strain sensing behavior of a putty, but with the structural durability of an advanced silicone rubber. Curing memorysil with graphene infused is a simple process. 

    Practical Applications
    • G-Putty: Best suited as a printed sensor ink, wearable medical patch on the skin, or acoustic/vibration monitor where the material is sealed inside a protective casing. However, the fact that G-putty needs to be incased in a container is its biggest disadvantage compared to Memorysil with graphene.
    • Graphene MemorySil: Ideal for smart mattresses, robotic finger grips, or advanced aerospace cushions that need to actively monitor shifting posture and weight distribution over years of physical abuse without ever breaking down. Graphene memorysil is just as sensitive as G-putty with nearly the same guage factor.

    MemorySil provides excellent mechanical energy dissipation through its massive hysteresis loops, but its ultra-low stiffness results in poor overall shock attenuation against concentrated, high-energy impacts.
    According to an official laboratory test report from impact protection experts D3O, MemorySil functions more like a slow-yielding cushion than a heavy-duty armor plating. 

    High Hysteresis and Dissipation
    • Massive Energy Loops: MemorySil exhibits exceptionally high hysteresis in both tensile and compression tests.
    • Energy Absorption: When compressed or stretched, the internal structure absorbs and dampens mechanical energy rather than storing it like a rigid spring.
    • Rapid Shape Recovery: Despite absorbing energy like a slow putty, the material is elastic enough to return to its original molded shape fairly quickly, maintaining consistent damping properties across multiple impacts.

    The Core Flaw: Too Soft for Heavy Shocks
    • High Transmitted Force: Under a standard 5-Joule impact test, MemorySil transmits a dangerously high amount of force—making it at least 5 times worse at blocking sudden shocks than standard D3O protective materials (like SE004) (p. 7).
    • Insufficient Structural Stiffness: Because the material is so soft, it lacks the compressive resistance needed to halt a fast-moving object (pp. 5, 7). It quickly compresses down to nothing under an impact, failing to absorb the bulk of the kinetic energy (p. 7).
    • Prone to Puncturing: Due to its low ultimate tensile strength, sharp or highly localized impact forces easily pierce completely through MemorySil sheets (pp. 5, 7, 9).

    Ideal Practical Implementation
    Because it cannot handle isolated, high-speed impacts on its own, D3O engineers recommend using MemorySil exclusively alongside a rigid backing material (pp. 7, 9). A hard plate or stiff layer can spread an incoming blow across a massive surface area, allowing MemorySil's soft, high-dissipation properties to safely soak up the remaining vibration without bottoming out or tearing
    Medical Cushions and Decubitus Ulcer Prevention
    • Adaptive Wheelchair and Bed Padding: Standard silicone or foam mattresses exert continuous, uniform counter-pressure against the skin, which cuts off capillary blood flow and causes bedsores (decubitus ulcers). MemorySil temporarily yields to an ultra-low stiffness when localized bony prominences press against it. It wraps smoothly around the body's precise shape, maximizing the contact area and reducing localized peak pressures to near zero.
    • Prosthetic Socket Liners: Amputee residual limbs experience shifting friction and pressure throughout the day. A MemorySil liner would automatically adjust its thickness to fill the volumetric gaps inside a prosthetic socket as the limb naturally swells or shrinks, minimizing chafing and skin breakdown.
    2. High-Fidelity Audio and Virtual Reality Interfaces
    • VR/AR Headset Facial Interfaces: Traditional foam or rubber gaskets on virtual reality headsets press hard against the forehead and cheekbones, causing discomfort and red marks ("VR face"). MemorySil contours perfectly around unique facial bone structures without building up high skin pressure, while forming a total, comfortable light seal.
    • Over-Ear Headphone Cushion Inlays: Using MemorySil in the structural core of headphone ear cups would allow them to conform effortlessly around glasses frames, blocking external ambient noise completely without pinching the user's head.
    3. Vibration Isolation and Precision Manufacturing
    • Acoustic Subwoofer and Turntable Isolators: Because MemorySil has a massive internal hysteresis loop, it acts as an exceptional energy sink. Placed beneath heavy audio equipment or high-precision lab scales, it completely dampens continuous floor vibrations and resonance, converting the kinetic energy into slight internal heat rather than reflecting it back into the device.
    • Adaptive Fixturing Gaskets: In robotic assembly, holding delicate, highly irregular components (like blown glass or rough castings) can crack the parts. MemorySil pads on robotic grippers can safely mold themselves entirely around an awkward, fragile shape to get a solid, non-slip hold without exerting fracturing pinch-forces.
    4. Ergonomic Wearables and Tooling
    • Custom-Contoured Tool Grips: Wrapping high-vibration power tools (like jackhammers, drills, or dental tools) in a layer of MemorySil creates a grip that dampens high-frequency mechanical buzz before it reaches the hands, which helps protect operators from long-term nerve damage (Hand-Arm Vibration Syndrome).
    • Podiatric Orthotics and Shoe Insoles: Used as a targeted heel or metatarsal insert, MemorySil accommodates the foot's impact zone during a step, molding dynamically to the stride. Because it has a delayed recovery, it delays pushing back until the foot is already lifting off the ground, reducing repetitive strain.

    Arxiv and other online references



    • Patent Title: Viscoelastic silicon rubber compositions
      • Patent Number: US 8,785,507 B2
      • Filing Date: March 9, 2011
      • Issue Date: July 22, 2014 [1]
    • Patent Title: Viscoelastic silicon rubber compositions
      • Patent Number: US 9,550,864 B2
      • Filing Date: August 10, 2012
      • Issue Date: January 24, 2017 [1]


    Enclosed mold. Platinum or peroxide. Part a+B. 350F @8 minutes. closed cell Foamed version available. 

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