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Title: Soft responsive objects that use catalysis as a design tool
Author: Jaggers, Ross William
ISNI:       0000 0004 7227 9549
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2018
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In this thesis, we have developed a series of chemoresponsive soft polymer objects that have either biological or inorganic catalysts integrated into them, namely the enzyme urease or particles of manganese oxide, respectively. Firstly, we show the fabrication of soft hydrogel fibres and beads that have an individually programmed time delay in their response to a shared environmental stimulus. We utilise the enzyme urease to programme a self-regulated change in pH, which in turn activates fibre disintegration or a change in gel bead colour. This design allows for independent response behaviour of a collection of bodies in a single closed system, as well as inter-material communication on shorter length scales. Secondly, we create continuous objects of non-uniform dimensional composition that selectively respond to an environmental stimulus of urea and change colour or disintegrate at pre-defined locations within the hydrogel structure after pre-set time intervals. This gives objects both time and spatial programming, again using the enzyme urease. Thirdly, we demonstrate more complex chemical communication between millimetre-sized soft hydrogel beads in an aqueous environment. Silver cations (Ag+) and the Ag+ chelator dithiothreitol (DTT) are used as signalling molecules, and by exploiting their interplay, we conduct a series of ‘conversations’ between urease containing millimetre-sized beads. Competitive communication between three beads, whereby the central bead receives two competing signals from two senders, is shown. Lastly, we show giant polymer capsules which have membrane-embedded catalytically active manganese oxide particles, made using droplet-based microfluidics. It is demonstrated that these colloidal particles can regulate the membrane permeability of the capsules upon their exposure to, and catalytic reaction with, small amounts of dissolved hydrogen peroxide.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry