Colloidal Stable PIC Vesicles and Lamellae Enabled by Wavelength-Orthogonal Disulfide Exchange and Polymerization-Induced Electrostatic Self-Assembly

Abstract

Block copolymer nanoparticles have been widely used for advanced materials. However, the stabilization is challenging. Herein, we present a method for convenient yet reliable synthesis of stabilized polyion complex (PIC) nanometer-sized spheres and micrometer-sized ultrathin lamellae and vesicles by taking advantage of the wavelength orthogonality of UV-induced disulfide exchange and visible light-initiated polymerization-induced electrostatic self-assembly (PIESA). Disulfide-containing PIC vesicles are synthesized at scale using this PIESA, undergoing a small sphere-to-larger sphere-tolamella-to-vesicle transition. As such, surface-neutralized and surface-charged micrometer-sized vesicles can be achieved. UV irradiation of the vesicles (5.0 mg/mL in water) in ambient air induces very fast exchange reaction of locally confined/enriched disulfide motifs, leading to cross-linking, shape transition, and cystamine salt release in 4 min. As such, cross-linked PIC spheres, lamellae, and vesicles can be achieved, in one pot, from one single vesicle precursor. The wavelength orthogonality is evident from disabled PIESA synthesis under UV light and ineffective postpolymerization functionalization under visible light. The cross-linked PIC spheres and micrometer-sized ultrathin lamellae and vesicles show outstanding shape/size stability and high reversibility in the solution-adaptive electrostatic hierarchical self-assembly and disassembly upon adding ethanol into aqueous dispersion and subsequent dialysis.

Efficient Synthesis of Stable Polyelectrolyte Complex Nanoparticles by Electrostatic Assembly Directed Polymerization

“…[ 12 ] Although template polymerization has achieved controlled and scalable synthesis of coacervate nanoparticles at appreciable concentrations, the reported methods so far rely on pure electrostatic interactions, so the obtained nanoparticles are sensitive to ionic strength: salt screens the charge interaction between the polyelectrolyte building blocks and eventually the nanoparticles dissociate. [ 5 a, 13 ] Such a limited stability constrains their applications, and therefore, post cross‐link is applied normally in order to enhance their stability for different applications. [ 14 ]…”

Access to Photoreactive Core‐Shell Nanomaterials by Photoinitiated Polymerization‐Induced Self‐Assembly

“…Generally, reversible‐deactivation radical polymerization (RDRP) is the underpinning mechanism for PISA ( i. e ., RDRPISA), under either dispersion or emulsion conditions. While thermal initiation is applied in most RDRPISA systems, photoinitiation has more recently been exploited and is attractive owing to its relatively low energy demand, the consequently reduced occurrence of side reactions or changes to temperature‐responsive morphologies, and a potentially higher compatibility with temperature‐sensitive moieties …”

One‐Step Preparation of Thermo‐Responsive Poly(N‐isopropylacrylamide)‐Based Block Copolymer Nanoparticles by Aqueous Photoinitiated Polymerization‐Induced Self‐Assembly

“…[ 8 ] Recently, reversible addition‐fragmentation chain transfer (RAFT)‐mediated polymerization‐induced self‐assembly (PISA) offers new opportunities for in situ preparation of stimuli‐responsive block copolymer nanoparticles at high solids contents (10–50 wt%). [ 9–23 ]…”