of the various molecular pathways involved. The molecular pathway of interest can in principle always be made dominant by switching off other pathways completely or asymptotically. In order to study the kinetics of nucleated polymerisation we first transform the molecular pathways into the corresponding reaction representation. $$\begin{aligned}
 \label{eq1}
& \text{i) primary nucleation} \hspace{85pt} n_c x \xrightleftharpoons[k_n^-]{k_n^+} y_{n_c},  \\
& \text{ii) end evaporation and addition} \hspace{26pt} y_i + x \xrightleftharpoons[2 k_e^-]{2 k_e^+} y_{i+1}, \\
& \text{iii) body evaporation and addition} \hspace{19pt} y_i + x \xrightleftharpoons[k_b^-(i-1)]{k_b^+(i-1)} y_{i+1}, \\
& \text{iv) scission and recombination} \hspace{40pt} y_i + y_j \xrightleftharpoons[k_f^-]{k_f^+} y_{i+j} \quad \text{for} \quad i,j \le n_c,\end{aligned}$$ where $x$ and $y_i$ are the concentration of monomers and that of polymers of degree of polymerisation $i$, respectively, and $n_c$ is the critical nucleus size, i.e., the degree of polymerisation of smallest stable polymer. Furthermore, $k_n^+$, $k_n^-$, $k_e^+$, $k_e^-$, $k_b^+$, $k_b^-$, $k_f^+$ and $k_f^-$ are the rates of nucleus formation and disintegration (subscript n), monomer addition and removal from the ends (subscript e), the rates of monomer addition and removal from the polymer backbone excluding the ends (subscript b) and polymer recombination and scission (subscript f). The factor of $i-1$ in reaction iii), describing body evaporation 