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Abdel Chakiri coauthored a 2015 study with Philip Hodge on ring-opening metathesis polymerization of macrocyclic olefins prepared from deoxycholic acid. The primary manuscript gives the Manchester chemistry affiliation and describes functionalized polymers and film formation.^[ref]

The scientific idea is to use molecular building blocks that carry useful functional groups into the resulting polymer, rather than treating the chain backbone as the only design variable. A polymer repeat unit can describe a recurring structural contribution, while the final material also depends on its chain lengths, end groups and retained functionality.

For an original bookkeeping example, suppose an ideal polymerization converts 100 macrocyclic building blocks into long chains without losing their repeat-unit mass, and each building block carries two accessible hydroxyl groups. The product contains 200 such groups regardless of whether it forms one chain or ten. If the repeat contribution is $500\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$, that corresponds to $2/500=4\mathrm{mmol}{\mathrm{g}}^{-1}$ of groups in the end-group-neglecting model. Changing the number of chains changes average molecular size but not that stipulated functional-group loading.

The assumption of two surviving accessible groups per unit must be tested, not inferred from a synthetic scheme alone. Spectroscopy or chemical analysis can examine structure; film formation and mechanical testing examine different properties. The manuscript's proposed use of films for supporting cell growth should likewise be distinguished from a demonstrated biological or clinical result. The numerical loading above is illustrative and is not assigned to Chakiri's actual polymers.

Philip Hodge investigated ring-opening metathesis polymerization of macrocycles. In a 2015 study with Abdel Chakiri, he prepared functionalized polymers from macrocyclic olefins derived from deoxycholic acid. The primary manuscript reports film formation and discusses potential materials applications.^[ref]

The work illustrates an alternative to explaining every ring-opening reaction solely by release of strain in a small ring. For sufficiently large rings, the balance between rings and chains can depend strongly on entropy and concentration. The thermodynamic question is the change in Gibbs free energy,for a specified reaction and state, including the relevant activities.

For an original numerical illustration, a stipulated reaction with $\Delta H=0$ and $\Delta S=20\mathrm{J}\mathrm{mo}{\mathrm{l}}^{-1}{\mathrm{K}}^{-1}$ at $298\mathrm{K}$ has $\Delta G=-5.96\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. This demonstrates how a favorable entropy contribution can supply the free-energy decrease without a negative enthalpy change. It does not assign those values to Hodge's experimental macrocycles.

Functional groups retained in the resulting material provide another design variable beyond chain formation. Film formation, mechanical performance and suitability for contact with cells are separate tests: a transparent film is not by itself proof of a biological effect. The example connects molecular architecture, thermodynamics and material characterization without promoting a proposed use to an established result.