The solution behaviour of water soluble polymers can be demonstrated via the introduction of fluorescent markers to the polymer chain. These fluorescent polymers can then act as probes, capable of being utilised in a range of applications both industrial, biomedical and to further our understanding of basic polymer physics.Reversible addition-fragmentation transfer (RAFT) polymerisation was used to synthesise a range of poly(acrylic acid) (PAA) polymers of varying molecular weight, each containing a luminescent label used to study the conformational state of the polymer backbone. This work demonstrates a molecular weight dependence in the pH responsive conformational change, as it was found that polymers with a molar mass lower than 17 kDa did not coil at low pH.Figure 1 � Poly(acrylic acid) is known to change its conformation in response to the pH of solution. The fluorescence lifetime ???? falls from 35 to 25 nanoseconds as the polymer swells at high pH. However by manipulating the molecular weight of these probe polymers this stimuli responsive behaviour is inhibited.These polymers were also used as dynamic polymer probes, forming interpolymer complexes with other polymers in solution and acting as a low concentration detector for polymeric impurities. Utilising this methodology a comparison between the strength of binding between poly(acrylic acid) and poly(acrylamide), poly(N-isopropyl acrylamide) and a range of other compatible hydrogen bond receptors is possible.

Fluorescence labelled dynamic polymer probes: Examining solution behaviour and polymer-polymer interactions

248th National Meeting (2014)

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