Facile polymerization in a bicellar template to produce polymer nano-rings

Synthesis of Polymer Nanoweb via a Lipid Template

“…The high-C lp system is presumably a morphological mixture of bicellar discs and perforated lamellae (some of them possibly constituting the shell of the vesicles), with PS shielded by DHPC, as previously reported in similar systems at lower S/L ratios. 16 However, the large-quantity PS in the current PS/L system further extends and connects (either in the bilayer to minimize the hydrophobic mismatch between DHPC and DPPC or through the aqueous phase) to the nearby PS residing in the DHPC-rich defects, eventually forming interconnected three-dimensional "webs", as confirmed by TEM (Figure 2), AFM (Figure S7), and SEM (Figure S8) after removing lipids.…”

“…19,26 Here, we utilized the same compositions of DPPC, DHPC, and DPPG as our previous report, which showed stable bicelles even after styrene-or polystyrene-encapsulation. 16 Their spontaneous morphology is dictated by hydrophobic interactions, segregation of gel-phase and fluid-phase lipids, spontaneous molecular curvatures, mismatch in aqueous solubility between long-and shortchain lipids, and surface charge density. 19 Using this bicellar template, a well-defined polystyrene nanoring is attainable in an aqueous solution as (styrene monomer + divinylbenzene cross-linker)-to-lipid, ( and this strategy is proven applicable for multiple hydrophobic vinyl monomers.…”

“…19 Using this bicellar template, a well-defined polystyrene nanoring is attainable in an aqueous solution as (styrene monomer + divinylbenzene cross-linker)-to-lipid, ( and this strategy is proven applicable for multiple hydrophobic vinyl monomers. 16 Here, we report that a model monomer, styrene, and a crosslinker, divinylbenzene (DVB) can generate polymer nanoweb, instead of nanorings, when ([S] + [DVB])/[L] ratio is above 0.1 in DPPC/DHPC/DPPG system. Two important findings include (1) morphological transformation from discoidal bicelles to lamellae upon the addition of overwhelming styrene monomers, and (2) formation of polystyrene nanoweb after removal of the lipid scaffold as confirmed by small angle neutron scattering (SANS), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM).…”

“…This observation agrees with the previous report for samples with lower S/L ratios. 16 Furthermore, the fact that Bragg peaks appear in the CM-SANS data of dPS/L, instead of dS/L data (Figure 3a), indicates breaking of the CM condition due to the demixing of dPS from DPPC. For the dS/L system, we utilized a recently developed five-layer core−shell discoidal model (5LCSD, Figure 3b and Supporting Information), 41 which describes the bilayer neutron scattering density (NSLD) profile as phosphate-all trans−trans/cis−all trans-phosphate (Figure 3b) across the bilayer, to best-fit the CM-SANS data (Figure 3a).…”

“…The polymerization induced segregation between PS and DPPC was previously reported in the lower S-to-L ratios. 16 The fact that the discs are not dissociated from each other after dilution into C lp = 0.003 wt %, but form aggregates as shown in Figure 2a,b, also suggests that PS "strings" discs together possibly through the PS at the rim. The observed empty circles in the TEM (Figure 2c) agree with such a presumption.…”