Styrene

Silica particles (R_c=57±6 nm) were obtained from Nissan Chemicals. Styrene (S) was obtained from Aldrich and purified by passing through an alumina-filled column. The synthesis of PS-grafted particle brush systems was performed using surface-initiated atom transfer radical polymerization as described previously16 17 (link). The polymer grafting density σ=0.5–0.6 chains per nm² was determined by elemental analysis as well as thermogravimetry. The molecular weight distribution of surface-grafted chains was determined by size exclusion chromatography after dissolution of the particle core in hydrofluoric acid. The graft characteristics of the particle systems, grafting density σ, degree of polymerization N (=130–980) of the surface tethered chains are listed in Table 1.

GMA (97%) and styrene (S) (99%) were purchased from Aldrich (Saint Louis, MO, USA). They were purified by passing them through columns packed with inhibitor remover and then stored in a sealed flask under a head of nitrogen in a refrigerator, until needed.
N-(2-Methylpropyl)-N-(1-diethylphosphono-2, 2-dimethylpropyl)-O-(2-carboxylprop-2-yl) hydroxylamine (99%, SG1, Arkema) was used as received. N-Hydroxysuccinimide (98%) and N,N′-dicyclohexylcarbodiimide (DCC, 99%), both from Aldrich (Saint Louis, MO, USA), were reacted with SG1 to produce the succinimidyl ester terminated alkoxyamine (NHS-SG1), according to literature procedures [47 (link),48 (link)].
l-lactide was purchased from Purac (Gorinchem, Netherlands) and was used for polymerization after purification by recrystallization from Ethyl acetate solution followed by 3 h of drying under vacuum. Ethyl acetate, stannous octoate Sn(Oct)₂, (95%), and 1-dodecanol (98%) were purchased from Aldrich (Saint Louis, MO, USA), and were used as received. 1-dodecanol was purified by distillation under reduced pressure before use. All reagents used were analytical grade.

Tetrahydrofurane (THF), N,N-Dimethylformamide (DMF), Methanol, 2-hydroxyethyl acrylate (HEA) and styrene (S) were purchased from Sigma-Aldrich and were used as received. (N-tert-butyl-N-(1′-diethylphosphono-2,2′-dimethylpropyl)-O-(2-carboxyl-prop-2-yl) (MAMA-SG1) alkoxyamine initiator (registered as trademark BlocBuilder by Arkema) and N-tert-butyl-N-(1′-diethylphosphono-2,2′-dimethylpropyl) (SG1, 85%) free nitroxide were provided by Arkema and were used as received.
The chemical structure and composition of the block copolymer was investigated by proton nuclear magnetic resonance spectroscopy (¹H NMR) and Fourier Transform Infrared (FTIR) spectroscopy. NMR experiments were performed with a Bruker Avance III 400 MHz Nanobay spectrometer. ¹H NMR spectra were recorded at a frequency of 400 MHz with a 11.3 μs 30° pulse, a repetition time of 4 s and 16 scans. NMR chemical shifts were reported in standard format as values in ppm relative to deuterated solvents. Infrared analysis was carried out using a Perkin Elmer Spectrum 2 equipped with a single reflection diamond module (ATR). IR spectrum was recorded in the 400–4000 cm⁻¹ range, at 4 cm⁻¹ resolution.

Wheat and buckwheat flour was purchased from a local supermarket in Dalian, Liaoning, China. Standard chemicals: analytical grade (pentanal, hexanal, heptanal, octanal, nonanal, decanal, 1‐penten‐3‐ol, pentanol, hexanol, heptanol, octanol, toluene, ethyl benzene, p‐xylene, styrene, 2‐pentyl‐furan, and C4–C20 n‐alkanes) were purchased from Sigma‐Aldrich. Internal standards (tetracosane, p‐chloro‐L‐phenylalanine, 5R‐cholestan‐3β‐ol, Phenyl‐β‐D‐glucopyranoside) were purchased from Aladdin.

All reactions were performed in a Unilab MBraun Glovebox with a nitrogen atmosphere. sec-Butyllithium (sec-BuLi, Sigma Aldrich, 1.4 M in cyclohexane), butylhydroxytoluene (BHT) (TCI, >99.0%), chloroform-D (CDCl₃, Cambridge Isotope Laboratories Inc., 99.8%), methanol (MeOH, 99.8%, Fisher Scientific), and dichloromethane (DCM, 99.5%, Fisher Scientific) were used without further purification. Styrene (Sigma Aldrich, 99+%), isoprene (Sigma Aldrich, 99+%), and diphenylethylene (DPE, Sigma Aldrich, 97%) were dried over calcium hydride (CaH₂) (ACROS organics, 93% extra pure, 0–2 mm grain size) for a minimum of 24 h. Styrene and DPE were vacuum transferred and degassed by three freeze–pump–thaw cycles. Isoprene was vacuum transferred onto activated 4 Å molecular sieves (EMD Chemicals, 8–12 mesh beads) for further drying and after 48 hours was vacuum transferred and degassed by three freeze–pump–thaw cycles. Molecular sieves were activated under vacuum at 180 °C overnight. Cyclohexane was degassed by two freeze–pump–thaw cycles before a 1 : 1.2 molar ratio of DPE and sec-BuLi was added under a nitrogen blanket until a deep red colour was sustained. This solution was stirred for a minimum of 1 hour. Cyclohexane was distilled under nitrogen from the DPE/sec-BuLi and additionally degassed by three freeze–pump–thaw cycles.