## 4 Experimental Methods  
_Materials_: Unless otherwise stated, all reagents were used as received and without further purification, and all procedures were conducted under an inert argon atmosphere using standard Schlenk line techniques. Divinylbenzene 80% (DVB-80, technical grade, 80% difunctional monomer (\(m\)- and \(p\)-DVB), 20% monofunctional monomer (3- and 4- ethylstyrene)), lauryl methacrylate (LMA, 96%, 500 ppm MEHQ as inhibitor), lauryl acrylate (LA, technical grade 90%, 60-100 ppm monomethyl ether hydroquinone as inhibitor), stearyl methacrylate (SMA, mixture of stearyl and cetyl methacrylate, containing MEHQ as inhibitor), stearyl acrylate (SA, 97%, contains 200 ppm monomethyl ether hydroquinone as inhibitor), cyclohexanone (99%+), deuterated chloroform (99.8%+), tetrahydrofuran (THF, anhydrous, 99%+) and 2,2^-azobis(isobutyronitrile) (AIBN, 98%+) were all purchased from Sigma-Aldrich, UK. The commercially purchased PAO4 base oil was supplied by bp Applied Sciences, Pangbourne, UK and used as received. High-purity argon was purchased from BOC gases, UK. The externally purchased mediating agents bis[(difluoroboryl)diphenylglyoximato]cobalt(II) (CoPhBF) was obtained from DuPont and 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO, 98%) was purchased from Sigma-Aldrich, UK. Cyclohexanone solvent was purchased from Fischer, UK. Toluene solvent was obtained directly from the chemistry stores. _Synthetic Procedures - Note on Gelation_: Gelation was defined as the point at which the solution ceased to be a free-flowing, easily stirred liquid and became a rubbery/solidified gel. This point was a readily observable change in physical form and apparent through visual inspection. However, in all cases, gelation was confirmed by withdrawing a small sample of the reaction mixture and attempting to dilute it in chloroform. Where gelation had occurred, the resultant sample presented as non-redissolvable material in the resulting solution. The time at which this occurred was defined as the gelation time and represented a change from an oligomeric/hyperbranched system to an extended, 3D, cross-linked system. _Direct Nitroide Mediated (NMP) and CCTP Mediated Copolymers of DVB and Lauryl/Stearyl (Meth)acrylate:_ Copolymers were produced via the CCTP mediated reaction of DVB (2.0 mL, 1.828 g, 14.0 mmol) or by either LMA, LA, SMA or SA (8 mL, 27.3 mmol, 29.4 mmol, 20.4 mmol, 19.7 mmol). The desired quantities of these monomers, cyclohexanone (10 mL, 9.48 g, 96.6 mmol) and mediating agents were introduced into a Schlenk flask equipped with a magnetic stirrer bar and containing an inert argon atmosphere. No initiator was included in the reagent formulation because both styrene and DVB are known to self-initiate at reaction temperatures of approximately 150 \({}^{\circ}\)C. Thus, the reaction was allowed to self- initiate to produce the HBs, as has previously been reported by the authors [37]. For the methacrylate species 2,2,6,6,6-(tetramethylpiperidin-1-yl)oxyl (TEMPO, 46 mg, 0.294 mmol) was used as the polymerisation mediating agent, and for the acrylate species, bis[(difluoroboryl)diphenylglyoximato]cobalt(II) (PhCoBF, 26 mg, 0.0401 mmol). For both monomer families, the reaction vessel was then immersed in a preheated oil bath which was thermostatically controlled to remain at 150 \({}^{\circ}\)C. The initial reactions were run until gelation occurred, at which point the time was noted, and a repeat reaction was conducted. This repeat reaction was quenched 15 min before the time gelation was known to occur in the initial scouting experiment. Once cooled, the solution was added dropwise to cold (0 \({}^{\circ}\)C) methanol. The resulting precipitation was collected via filtration to provide a colourless (NMP experiments) or brown/white, viscous liquid (CCTP experiments colouration due to PhCoBF), which was then dried to constant mass under vacuum. _Synthetic Procedures: Preparation of Crude Lauryl Methacrylate (LMA) Oligomers:_ A solution of mixed LMA oligomers was synthesised via CCTP of LMA monomer.