Photonics in polymer chemistry

Light has been an important resource in polymer chemistry since the introduction of photo-initiated polymerisations. As this is, however, not the topic of this section, we will focus on advanced applications of light in polymer science including two-photon polymerisation and light-responsive materials. 

An interesting processing technique applying light in material science is two-photon polymerisation [2PP] [127, 148]. Using 2PP, a photo-curable material is subjected to spatially well-defined laser irradiation [Fig. 21.19]. 

Since two photons are required to initiate the polymerisation, curing will only take place in the focal point of the laser [i.e. where the concentration of photons is the highest]. The microscope objective used to focus the laser beam can be moved relative to the sample. After removal of the uncured material, complex three-dimensional structures can be achieved via direct laser writing [127, 149]. Interestingly, biodegradable polyester oligomers have 

Light-responsive materials make up a second example of using light in polymer science to introduce novel functionalities. These materials change their characteristics upon irradiation with a 

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