computational modelling comes in: Predictive mechanical models cast light on the
mechanisms underpinning the enhanced performance and may give direction or
identify promising formulations in the search for further improvements.
In this paper, we delve deeper into some exciting recent advances based on the
use of reversible linkers and composition in hydrogels and elastomers and review
some of essential computational techniques required to model these materials. In the
concluding sections, we share some recent and new results that demonstrate the
potential of such approaches: at various length scales, from molecular to bulk,
simulations allow us to ask and answer some basic questions that relate structure,
dynamics and properties in modern polymeric materials. While this overview is
obviously non-exhaustive, we nonetheless hope to convince the reader that spaghetti
and snakes no longer suffice to capture the exquisite, rich and surprising mechanical
performance of the next generation of polymer materials.
2 Background: Topology and Dynamics in Network
Materials
2.1 Composite Materials
2.1.1 Polymer-Polymer Composites: Homocomposites and Multiple
Networks
Composites are ubiquitous, found in nature or synthetically engineered to solve
complex functional problems. They are a combination of two or more constituents,
working together as a cohesive unit to showcase high-calibre mechanical performance, typically unattainable by a material composed of single constituent.
Polymer-based composites including fibreglass, carbon fibre and shape-memory
polymer have wide applications in automotive, aerospace, construction and sporting
industry for their low cost, strength, flexibility and renewability. The human body
contains multiple composites of proteins that are essential for optimal function.
Cells, whether plant or animal, are made up of cytoskeleton – a complex network
of filaments and tubes. Homocomposites are a subset of composites built from the
same chemical unit. Polymer-polymer homocomposites consist of identical polymer
networks, covalently bonded or purely entangled to each other. Each network has its
unique structural identity, even though they can be chemically identical.
Homocomposites are a shining example of camaraderie between chemistry and
design ingenuity – leading to hybrid materials showcasing high performance and
sustainability.
Traditionally elastomers have been toughened by combining a well-chosen glass
transition temperature, which sets the temperature range of viscous dissipative
mechanisms, and the use of nanofillers (like carbon black and silica). The nanofillers
introduce strain-dependent damage mechanisms and increase the stiffness of the
material at the same time [1] – more on this in Sects. 2.1.2 and 4.5. However,
66
C. Raffaelli et al.
mechanisms underpinning the enhanced performance and may give direction or
identify promising formulations in the search for further improvements.
In this paper, we delve deeper into some exciting recent advances based on the
use of reversible linkers and composition in hydrogels and elastomers and review
some of essential computational techniques required to model these materials. In the
concluding sections, we share some recent and new results that demonstrate the
potential of such approaches: at various length scales, from molecular to bulk,
simulations allow us to ask and answer some basic questions that relate structure,
dynamics and properties in modern polymeric materials. While this overview is
obviously non-exhaustive, we nonetheless hope to convince the reader that spaghetti
and snakes no longer suffice to capture the exquisite, rich and surprising mechanical
performance of the next generation of polymer materials.
2 Background: Topology and Dynamics in Network
Materials
2.1 Composite Materials
2.1.1 Polymer-Polymer Composites: Homocomposites and Multiple
Networks
Composites are ubiquitous, found in nature or synthetically engineered to solve
complex functional problems. They are a combination of two or more constituents,
working together as a cohesive unit to showcase high-calibre mechanical performance, typically unattainable by a material composed of single constituent.
Polymer-based composites including fibreglass, carbon fibre and shape-memory
polymer have wide applications in automotive, aerospace, construction and sporting
industry for their low cost, strength, flexibility and renewability. The human body
contains multiple composites of proteins that are essential for optimal function.
Cells, whether plant or animal, are made up of cytoskeleton – a complex network
of filaments and tubes. Homocomposites are a subset of composites built from the
same chemical unit. Polymer-polymer homocomposites consist of identical polymer
networks, covalently bonded or purely entangled to each other. Each network has its
unique structural identity, even though they can be chemically identical.
Homocomposites are a shining example of camaraderie between chemistry and
design ingenuity – leading to hybrid materials showcasing high performance and
sustainability.
Traditionally elastomers have been toughened by combining a well-chosen glass
transition temperature, which sets the temperature range of viscous dissipative
mechanisms, and the use of nanofillers (like carbon black and silica). The nanofillers
introduce strain-dependent damage mechanisms and increase the stiffness of the
material at the same time [1] – more on this in Sects. 2.1.2 and 4.5. However,
66
C. Raffaelli et al.