## 6 Impact of Multi-Arm Topology on PCL-Based Polymer Properties for Drug Delivery
** \\ \hline -PEG\({}_{113}\)-b-PCL\({}_{102}\) & & & & & & & & \\ -PEG\({}_{113}\)-b-(HEMA-g- & -Linear & 1 & 27.6 & 58.6 & & & & \\ PCL\({}_{8}\))\({}_{13}\) & -Multiarms & 13 & –7 & 53.1 & & & 2010 & [165] \\ -PEG\({}_{113}\)-b-(HEMA-g- & -Multiarms & 26 & –17 & 45.1 & & & & \\ PCL\({}_{5}\))\({}_{26}\) & & & & & & & & \\ \hline \multirow{4}{*}{Star-shaped PCLs similar molecular weights (Mn \(\mathrm{\
u}\)\(\mathrm{\times}\)\(\mathrm{10}\) 300)} & & 1 & – & 57.5 & 61 & & \\  & 2 & – & 55.1 & 57 & & & & \\ \cline{1-1}  & 3 & – & 54.9 & 55 & & 2008 & [156] \\ \cline{1-1}  & 4 & – & 53.1 & 53 & & & & \\ \cline{1-1}  & 5 & – & 52.9 & 50 & & & & \\ \hline -PPEGA-b-(PCL-)\({}_{2}\) & & & 2 & – & 32.5 & & & 2009 & [166] \\ -PPEGA-b-(PCL-)\({}_{102}\) & & & 2 & – & 45 & & & \\ \hline -PCI\({}_{40}\)-b-PS\({}_{59}\) & & 1 & 27.7 & 55.7 & 102.5 & 32 & Lamellar & \\ -(PCL\({}_{2}\))\({}_{39}\)-b-(PS\({}_{2}\))\({}_{61}\) & & \(\mathrm{A_{2}B_{2}}\) & 4 & 17.2 & 54.5 & 103.1 & 17 & PCL cylinders. & 2009 & [85] \\ \hline \multirow{4}{*}{PEO\({}_{23}\)-PCL\({}_{4.3\mathrm{K}}\) PEO\({}_{23}\)-PCL\({}_{2.1\mathrm{K}}\) AB\({}_{2}\)} & & 34.4 & 53.5 & & 47 & & \\ \cline{1-1}  & 2 & 30.5 & 47.4 & & 40 & & & [167] \\ \hline -PCL & – & & 25 & 49.9 & \(-\)56 & 66 & – & \\ -PBA & – & – & – & 22 & – & – & Uniform & \\ -\(\mu\)-(PBA)\({}_{2}\)(PCL)\({}_{4}\) & & \(\mu\)-\(\mathrm{A_{2}B_{4}}\) & 6 & \(-\)7.8 & 44.8 & 26.3\({}_{\mathrm{PBA}}\) & 26 & nanofiber & \\ \hline -4a-PCL\({}_{3\mathrm{K}}\)-b-PDLA \({}_{1\mathrm{K}}\) & & & \(-\)4 & 23 & 50 & & 66 & Dense spherulites. & \\ \cline{1-1}  & 4a-PCL\({}_{3\mathrm{K}}\)-b-PDLA \({}_{1\mathrm{K}}\) & & & \(-\)4 & 80 & 140 & & 13 & No spherulites. & 2014 & [169] \\ \hline \multirow{4}{*}{LPCL\({}_{4.8\mathrm{K}}\) 35 PCL\({}_{3.7\mathrm{K}}\) 45 PCL\({}_{4.9\mathrm{K}}\) 45 PCL\({}_{4. This has resulted in the use of these types of polymers as a base for the preparation of monodisperse nanoparticles. Similarly, the utilization of PCL-Br as a macroinitiator for ATRP, followed by its crosslinking with divinylbenzene (DVB), facilitated the development of active star centers for the polymerization of polystyrene (PS). The PCL chains of this multi-arm star could undergo biodegradation by hydrolysis under alkaline conditions (Figure 4). Besides being biodegradable, the micro-domain sizes present in these structures indicate potential benefits in terms of micelle sizes and properties. The research conducted by [PERSON] (2018) focused on the crystallization mechanism of a mixture of a four-arm PCL-PLLA copolymer and a PLLA homopolymer showed that the variation of the PLLA length in this multi-arm structure has a significant effect on the crystallization state of the mixture and that the degradation behavior is closely related to the crystallization state of the mixtures. This highlights the ability of the multi-arm to alter the thermal properties of the entire mixture, not just the character of its own structure. Moreover, what is particularly remarkable is that, in addition to being able to regulate the thermal characteristics through the manipulation of the number or length of the arms in the copolymer, these topologies have demonstrated alterations in such features depending on the sequence of the chain. In the work of [PERSON]. [PERSON] et al. [PERSON] et al. (2017), it was noted that when PLA was present as the outer block, the sequenced copolymer presented two \(\mathrm{T_{m}}\) and \(\mathrm{T_{g}}\), characteristic of each segment, one crystalline and the other amorphous. This proves the separation of phases in the 6s-PCL-b-PLA branched star with six arms. As for the 6s-PLA-b-PCL, or the PCL is the outer block, only one \(\mathrm{T_{g}}\) was detected, which confirms the phase miscibility.