Polymerization-Induced Self-Assembly Promoted by Liquid–Liquid Phase Separation

Abstract

Polymerization-induced self-assembly (PISA) is a powerful method for the synthesis of polymeric kinetically frozen core nanoparticles. However, the PISA synthesis of biologically important polymeric fluidic materials is unexplored. Herein we present a liquid–liquid phase separation mode PISA. The proof of concept is established by means of complex coacervation in visible light-initiated RAFT dispersion polymerization of anionic monomer in the presence of a protonated polyethylenimine in water at 25 °C. We demonstrate a stage-by-stage nano to micron droplet growth mechanism via an increase in growing chain DP or electrical neutralization. Liquid coacervate droplets and their glassy nanowires or vesicles can be interconverted upon changing the ethanol/water solvent. As such, tunable construction of coacervate droplets and nanowires or vesicles can be achieved using this smart PISA method.

Nanostructured Multiphase Condensation of Complex Coacervates in Polymerization-Induced Electrostatic Self-Assembly

“…Particle size strikingly decreases upon the dilution to 25 mg/mL, but mildly to 1.0 mg/mL (Figure S14C) due to the droplet dripping, leading to neutralized (ζ = −0.68 mV, Figure S14B) 40 nm size spherical droplets (Figure S14D). These results clearly suggest the instinctive LLPS feature of this photoinitiated PIESA …”

“…Our group developed polymerization-induced electrostatic self-assembly (PIESA) , via the RAFT photopolymerization of cationic monomer in the presence of anionic polyelectrolyte in water at 25 °C. , This approach provided a platform for synthesis of polyion complex (PIC) nanoparticles with phase-separated internal structures . Furthermore, we proposed LLPS-PIESA for the scalable synthesis of size-controllable spherical droplets of complex coacervates. We envision that the nanostructured multiphase condensates can be achieved by the programmed condensation of preassembled spherical coacervates in a well-controlled LLPS-PIESA dynamic evolving aqueous medium.…”

Chemical Feedback in Templated Reaction-Assembly Networks

“…We note that in another PIESA process the polymerization with the template was slower than without the template. 18 We hypothesize that this difference with our system is caused by the ∼17 times larger template concentration that was used in this other case, which will increase the viscosity and thus slow down the overall polymerization kinetics.…”

“…The result of the competition between monomers and polymerizing blocks is that the concentration of template-bound monomer decreases, slowing down the polymerization rate at the template, as can be seen from the decrease in the slope of the monomer conversion during Phase II ( Figure 1 c). 18 …”

A Simple Route to Aqueous Suspensions of Degradable Copolymer Nanoparticles from Radical Ring-Opening Polymerization-Induced Self-Assembly (rROPISA)

“…Among the different polymerization processes in dispersed media, polymerizationinduced self-assembly (PISA) [9][10][11] has established as the most versatile and robust to generate a wide range of different diblock copolymer nano-object suspensions (e.g., spheres, [12] vesicles [13][14][15] or worms [16] ) without surfactant and with high solids contents (ca 10-50 wt.%). PISA has indeed shown extraordinary flexibility in terms of polymerization techniques and conditions used, [17][18][19][20] monomers polymerized, [16,[21][22][23][24] stimuli-responsiveness [23,[25][26][27][28] or potential applications. However, even though PISAderived nano-objects have been suggested for drug delivery or other biomedical applications, [12,21,[29][30][31][32][33][34][35] there is yet no strategy to achieve aqueous suspension of degradable, polyester-like nanoparticles by PISA.…”