Patented viscoelastic silicone

MemorySil = Silly Putty® + Elastomer

A shape-memory silicone rubber that temporarily molds to whatever presses against it, yet slowly returns to a permanent default shape. It feels like a liquid and a solid combined.

What is MemorySil?

In its most basic form, MemorySil is Silly Putty® combined with an elastomer: the characteristics of a non-Newtonian putty and a viscoelastic elastomer in 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. Recovery can take a few seconds or a few hours, depending on the formulation.

In one sentence: think of wet clay that magically remembers to turn back into rubber a few seconds after you stop touching it.

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The science

A polydimethylsiloxane network with sparse crosslinks and hydrogen-bonding additives, modeled by Maxwell-Wiechert relaxation.

Read the science →

Applications

Medical cushions, prosthetic liners, VR and headphone interfaces, vibration isolation, tool grips, orthotics.

See applications →

Table stabilizer

Passive, self-adjusting table-leg pads that stop a four-legged table from rocking, with no moving parts.

How it works →

Graphene sensors

Graphene-infused MemorySil as a durable touch and pressure sensor, compared with Trinity College Dublin’s G-putty.

Compare →

Impact testing

An honest look at a D3O laboratory report: excellent damping, poor stand-alone shock protection.

See the results →

Patents & curing

Patent numbers, PCT publications and basic curing instructions.

References →

Quick answers

What is MemorySil made of?

A polydimethylsiloxane (PDMS) network with a low density of covalent crosslinks, siloxane resin modifiers, and non-reactive plasticizing additives that form transient hydrogen bonds.

How hard is it?

MemorySil has no single durometer. It starts soft and, when pressed, temporarily drops to near zero stiffness, unlike a standard 10A elastomer which stays at a constant hardness.

How fast does it recover?

From a few seconds to a few hours, depending on the formulation.

Is it good for impact protection?

Not by itself. It dissipates energy very well, but it is too soft to stop concentrated high-energy impacts. Pair it with a rigid backing layer. See impact testing.

Who invented it?

Physicists at the University of Virginia; see the patents.