|dc.description.abstract||Composite materials generally consist of different components which individually
exhibit an entirely different material behaviour than within the composite. Here,
two immiscible liquids are stabilised with solid particles forming liquid-liquid
emulsions. Solid stabilised emulsions, also known as Pickering emulsions, have
been thoroughly studied and find application in many industrial sectors. In
these emulsions one liquid is generally suspended within the other in the form
of droplets. Inspired by computer simulations, it should be possible to create
a bicontinuous network of two immiscible liquids also stabilised with jammed
particles. This will result in an attractive new material which could find
possible industrial applications, for example as microreactors. This potential
bicontinuous, interfacially jammed emulsion gel was dubbed bijel.
Drawing together knowledge from different disciplines this thesis presents
an experimental route to bijel formation. Accessing a certain type of phase
separation called spinodal decomposition can be used to create a convoluted
arrangement of bicontinuous interfaces. Liquid-liquid interfaces can be stabilised
by exploiting the fact that solid particles can be irreversibly trapped at liquidliquid
interfaces. Once trapped, the presence of the particles demands a minimum
interfacial area between the two liquids. If the particles are jammed against each
other this will result in the stabilisation of the liquid-liquid interfaces.
To stabilise convoluted, bicontinuous interfaces in this way one type of
particles must be able to concurrently stabilise two types of curvatures. Over
the last three years it has been shown by several different research groups that
this is possible.
This thesis examines different types of temperature and pressure quenches on
binary liquid systems to reach spinodal decomposition in the presence of particles.
At the same time the ability of the particles to collect on the interfaces created
during such phase separations is tested. It is found that temperature quenches
through the critical point can lead to reproducible bijel formation resulting in
the first experimental presentation of bijels. Using confocal microscopy the bijel
formation process is studied in detail and properties of this new material are
examined. To obtain insight into the behaviour of slowly ageing soft materials xray
photon correlation spectroscopy is separately carried out on droplet emulsions.||en