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Soft and Biomechanics


Admission Requirements none


Building This course aims to provide an introduction to the mechanics of soft materials, of which biological materials are prominent examples. Soft materials are those that can be easily deformed by external stress, electromagnetic fields or thermal fluctuations: in other words everything that is wet, squishy or floppy.
Fundamental concepts of continuum mechanics

  • From particles to volume elements: the continuum hypothesis

  • Stress analysis

  • Strain and strain-rate

  • Conservation laws in liquids and solids

  • Constitutive equations for liquids and solids

  • Cauchy-Navier and Navier-Stokes equations

  • Examples of time independent flows

  • Walking on liquids and other exotic properties of viscoelastic fluids
    Polymer mechanics

  • Basic properties of polymer chains

  • Random walks and ideal chains

  • Force-extension of an ideal chain

  • Self-avoiding chains and Flory’s theory

  • Semiflexible polymers: the wormlike chain

  • Stretching DNA: the Marko-Siggia interpolation formula
    Liquid Crystals

  • The zoo of liquid crystals: nematics, smectics, cholesterics, hexatics and more

  • Frank elasticity

  • Equilibrium configuration in nematics

  • Topological defects in nematics

  • Coupling to external fields and the Fredericks transition

  • Nematodynamics
    Active Matter

  • Remarks on the physics of living systems

  • Collective behavior in animal groups: swarming/flocking/schooling and the Vicsek model

  • Collective behavior in robots and sperm

  • Active liquid crystals and the cell cytoskeleton

  • Spontaneous flow in active nematics

  • Active flow in proximity of topological defects

  • Cell mimicry in active droplets

  • Open problems
    Mechanics of adherent cells

  • Actin cytoskeleton and cell adhesion

  • Basic concepts of cell motility

  • The Young-Laplace law and the contractile network model

  • The effect of anisotropy and the Schakenraad ellipse

Course Objectives

The course main objective is to provide the students with a solid core-knowledge on the mechanics of soft and biomaterials, such that, after the course, the students will have enough background to independently learn about these topics from the specialized literature. In order to encourage this latter aspect, the course will consist of a combination of lectures and seminars given by the students.


Physics Schedule

Mode of instruction

Lectures and student seminars.

Assessment method

The grade will be assigned based on homework (1/3) and a final project consisting of a short essay (1/3) and an oral presentation on a research paper selected from the literature (1/3).


To have access to Blackboard you need a ULCN-account.Blackboard UL

Reading list

The booktitles and / or syllabi to be used in the course, where it can be purchased and how this literature should be studied beforehand.


Contactdetails Teacher(s):Dr.L.Giomi(Luca)