Beneficiation of valuable fine metal oxide particles generated during mining, comminution and processing has long been problematic for the mineral processing industry due to their poor floatability. To overcome this issue, selective adsorption of a polymer onto the target fine particles provides a potential solution. In this study, two novel poly(acrylamide)-block-poly(ethylene oxide) copolymers, featuring a terminal alpha-tocopherol (vitamin E) moiety, were synthesised by reversible addition-fragmentation chain-transfer (RAFT) polymerisation. These copolymers were designed to selectively target adsorption onto valuable iron oxide particles. The adsorption of the novel copolymers onto hematite, magnetite and silica were then studied via the depletion method. This revealed significantly higher adsorption affinity of the vitamin E-tagged block copolymers onto iron oxide particles over silica. The adsorption was further benchmarked against commercial polyacrylamides (PAMs), a PAM modified with a hydrophobic RAFT agent, poly(ethylene oxide) (PEO) homopolymers and the vitamin E molecule. Isotherms indicate the vitamin E molecule and PEO homopolymers have higher affinity for silica than iron oxide, indicating the selectivity of the novel copolymers for iron oxide is driven by the PAM block. The prospective frother action of the copolymers was determined by measuring surface tension at the air-water interface. Overall, the novel poly(acrylamide)-block-poly(ethylene oxide) copolymers offer a step towards more sustainable mineral processing reagents.

Our custom copolymers enable tunable, pH- and concentration-dependent mesophase transitions in LNPs, offering enhanced control for targeted drug release.

Entropy-driven drying-mediated self-assembly of plasmonic nanocrystals (termed "plasmonic atoms") has emerged as a general strategy for fabricating plasmene nanosheets from a wide range of monodisperse nanocrystals. However, extending this approach to binary systems remains challenging due to the complex nanoscale interactions between dissimilar nanocrystal shapes. Here, we introduce a combined enthalpy- and entropy-driven strategy to achieve an orderly mixed two-dimensional (2D) binary nanoassemblies from complementary reacting polymer-ligated nanocrystals. Using nanocubes and nanospheres as model systems, "plasmonic molecules" were first synthesized via enthalpy interactions of different nanocrystals through stoichiometric reactions between complementary grafting polymers. This was followed by an entropy-driven, slow-drying-mediated assembly of "plasmonic molecules". This led to well-controlled binary plasmenes without phase separation. This method could be extended to a diverse range of other building block shapes and size scales. Our methodology indicates a new pathway for 2D nanocrystal assemblies with well-controlled mixing at nanoscale precision.

Fluorescence imaging has become a powerful technique in biomedical engineering and biomaterials science. Fluorescence probes exhibiting aggregation-induced emission (AIE) characteristics stand out as exceptional candidates for imaging due to their photostabilities and sensitivities. However, the hydrophobicity of the AIE functional groups limits their broad applicability. To overcome this limitation, we employed AIE by incorporating tetraphenylethylene (TPE) groups into amphiphilic blocks and random copolymers with varying lengths of 2-(dimethylamino)ethyl methacrylate (DMAEMA) segments. These new polymers demonstrate self-assembly behaviors forming fluorescent, core-shell micelles in aqueous environments and can serve as dual-functional stabilizers for monoolein-based lipid nanoparticles (MO-based LNPs) containing intricate inverse cubic (Q2) and hexagonal (H2) mesophases. Through rational design of incorporating DMAEMA, a pH-dependent enhancement in TPE fluorescent intensity for both nanosystems, the self-assembled polymer micelles and polymer-stabilized LNPs, was achieved. Successful fluorescence imaging of the novel polymer-stabilized LNPs was demonstrated in HeLa cells by confocal microscopy. This study represents the first instance of utilizing TPE- and DMAEMA-based block copolymers as fluorescent stabilizers for LNPs, with tunable fluorescent intensities by variations of DMAEMA block length and environmental pH. These findings underscore the significance of AIE block copolymers with tunable physicochemical properties for fluorescence imaging of nanomaterials in biological systems.

The effective separation of chalcopyrite, an extensively utilized copper mineral, presents a considerable hurdle for the mineral processing sector due to its geological tendency to be colocated with various sulfide minerals and its intricate surface chemistry that hinders efficient separation using conventional approaches. This research aims to address this challenge by utilizing Reversible Addition-Fragmentation Chain Transfer polymerization (RAFT) as a synthetic methodology for preparation of collector/flocculants to enhance the efficiency and selectivity of reagents for utilization in chalcopyrite flotation/flocculation. A RAFT polymer, poly(CA(4)-co-ACOEA(14)), was synthesized incorporating O-ethyl acetylcarbamothioate (R-O-C(& boxH;S)-NH-C(& boxH;O)-CH3) functionality for selective binding and cardanyl acrylate moiety as a hydrophobic component, with the goal of selective separation of chalcopyrite from pyrite. Laboratory experiments encompassing flotation/flocculation tests, adsorption assessments, and analyses utilizing UV spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy, and contact angle measurements were conducted to explore its performance in froth flotation and elucidate its adsorption mechanism on both mineral surfaces. A comparative study between poly(CA(4)-co-ACOEA(14)) and poly(CA(4)-co-XEA(14)), the latter is a polymer of similar molecular weight and hydrophobicity containing the xanthate functionality, demonstrated that poly(CA(4)-co-ACOEA(14)) exhibits superior performance. This enhanced efficacy could be attributed to the polymer's capacity to selectively adhere to the chalcopyrite surface, rendering it hydrophobic, while a comparable effect is not observed on pyrite due to weak adsorption. Furthermore, the flocculation performance of poly(CA(4)-co-ACOEA(14)) showcases its dual functionality as both a collector and a flocculant.

Abstract Aggregation‐induced emission (AIE) is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation‐caused quenching (ACQ). AIE has the potential to be utilized in the large‐scale production of AIE‐active polymeric materials because of their wide range of practical applications such as stimuli‐responsive sensors, biological imaging agents, and drug delivery systems. This is evident from the increasing number of publications over the years since AIE was first discovered. In addition, the ever‐growing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers, initiators and crosslinkers, with the goal of broadening the scope and utility of AIE polymers. One of the most promising approaches to the design and synthesis of AIE polymers is the use of the reversible‐deactivation radical polymerization (RDRP) techniques, which enabled the production of well‐controlled AIE materials that are often difficult to achieve by other methods. In this review, a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented, including (i) the design of AIE‐related monomers, initiators/crosslinkers; the achievements in preparation of AIE polymers using (ii) reversible addition–fragmentation chain transfer (RAFT) technique; (iii) atom transfer radical polymerization (ATRP) technique; (iv) other techniques such as Cu(0)‐RDRP technique and nitroxide‐mediated polymerization (NMP) technique; (v) the possible applications of these AIE polymers, and finally (vi) a summary/perspective and the future direction of AIE polymers.

Glioblastoma multiforme (GBM) is an aggressive brain cancer with high malignancy and resistance to conventional treatments, resulting in a bleak prognosis. Nanoparticles offer a way to cross the blood-brain barrier (BBB) and deliver precise therapies to tumor sites with reduced side effects. In this study, we developed angiopep-2 (Ang2)-functionalized lipid cubosomes loaded with cisplatin (CDDP) and temozolomide (TMZ) for crossing the BBB and providing targeted glioblastoma therapy. Developed lipid cubosomes showed a particle size of around 300 nm and possessed an internal ordered inverse primitive cubic phase, a high conjugation efficiency of Ang2 to the particle surface, and an encapsulation efficiency of more than 70% of CDDP and TMZ. In vitro models, including BBB hCMEC/D3 cell tight monolayer, 3D BBB cell spheroid, and microfluidic BBB/GBM-on-a-chip models with cocultured BBB and glioblastoma cells, were employed to study the efficiency of the developed cubosomes to cross the BBB and showed that Ang2-functionalized cubosomes can penetrate the BBB more effectively. Furthermore, Ang2-functionalized cubosomes showed significantly higher uptake by U87 glioblastoma cells, with a 3-fold increase observed in the BBB/GBM-on-a-chip model as compared to that of the bare cubosomes. Additionally, the in vivo biodistribution showed that Ang2 modification could significantly enhance the brain accumulation of cubosomes in comparison to that of non-functionalized particles. Moreover, CDDP-loaded Ang2-functionalized cubosomes presented an enhanced toxic effect on U87 spheroids. These findings suggest that the developed Ang2-cubosomes are prospective for improved BBB crossing and enhanced delivery of therapeutics to glioblastoma and are worth pursuing further as a potential application of nanomedicine for GBM treatment.

Reagent consumption is an ongoing sustainability challenge for the mineral processing industry. There is a need to recover, regenerate, and reuse as many of the chemical inputs as possible. This study investigated the design and synthesis via reversible addition-fragmentation chain transfer (RAFT) polymerization of a novel polymer for use as a surfactant in a water-in-oil (w/o) emulsion system for ultrafine minerals recovery. The polymers were designed to hold a thermoresponsive moiety to allow for future recovery. The performance of the novel emulsion was tested for agglomeration of ultrafine talc mineral particles. A traditional emulsion containing sorbitan monooleate as the surfactant was used as a research benchmark to compare against the novel emulsion's stability and performance in minerals recovery. The novel RAFT polymer-based emulsions formed large and stable water droplets surrounded by a halo of smaller water droplets. Over time, the smaller droplets coalesced and a more uniform size distribution of droplets was formed, keeping the emulsion stable. Rheological testing of freshly made and aged emulsions showed both traditional and novel emulsions to have a high viscosity at a low shear rate. RAFT polymer B with a hydrophilic-lipophilic block ratio of 5:10 performed adequately as a surfactant replacement to stabilize w/o emulsions. The mineral recovery using the novel emulsion was on par with the traditional emulsions. The novel RAFT emulsion containing 2.5 wt % polymer B achieved 90% minerals recovery, a similar yield to the traditional emulsions. This study demonstrates that surfactants containing stimuli-responsive moieties can be synthesized via RAFT polymerization and successfully used in mineral processing applications to recover ultrafine particles. Work is ongoing to exploit the stimuli responsiveness to recover the polymer surfactant for reuse.

Responsive nanoparticle delivery systems hold great potential for next-generation chemotherapeutic treatment with reduced off-target side effects. In this work, we formulated responsive lipid-based cubosomes loaded with paclitaxel (PTX) as a model drug and stabilised by novel amphiphilic block copolymers (ABCs) containing the pH-responsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and/or the hydrogen peroxide (H2O2)-responsive poly(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate) (PTBA) blocks. The results showed that these cubosomes with a particle size of around 250 nm exhibited excellent PTX encapsulation efficiency of up to 60% and had the ability to control the release rate of the drug in response to pH and H2O2 changes. Specifically, compared to the physiological pH of 7.4, PTX was released faster from the cubosome carriers when exposed to pH 5.5 and/or 50 mM H2O2 conditions, which are pathological conditions found in a tumour microenvironment. In vitro cytotoxicity and cell uptake studies further investigated the cellular interactions of these cubosomes. It was found that cubosomes containing PTX had more toxic effects than the control free PTX sample. Compared to cubosomes stabilised by the non-responsive block copolymer Pluronic® F127, the ABC-stabilised cubosomes also had higher cell internalisation efficiency demonstrated by the cytoplasmic fluorescence intensities using confocal microscopy. These results demonstrated that ABCs containing responsive moieties can stabilise lipid cubosomes and enhance controlled release of poorly soluble chemotherapeutics and cellular uptake.

Polymerization-induced self-assembly (PISA) combines polymerization and self-assembly in a single step with distinct efficiency that has set it apart from the conventional solution self-assembly processes. PISA holds great promise for large-scale production, not only because of its efficient process for producing nano/micro-particles with high solid content, but also thanks to the facile control over the particle size and morphology. Since its invention, many research groups around the world have developed new and creative approaches to broaden the scope of PISA initiations, morphologies and applications, etc. The growing interest in PISA is certainly reflected in the increasing number of publications over the past few years, and in this review, we aim to summarize these recent advances in the emerging aspects of RAFT-mediated PISA. These include (1) non-thermal initiation processes, such as photo-, enzyme-, redox- and ultrasound-initiation; the achievements of (2) high-order structures, (3) hybrid materials and (4) stimuli-responsive nano-objects by design and adopting new monomers and new processes; (5) the efforts in the realization of upscale production by utilization of high throughput technologies, and finally the (6) applications of current PISA nano-objects in different fields and (7) its future directions.

Keto-hydrazide cross-linking chemistry between diacetone acrylamide (DAAM) and adipic acid dihydrazide (ADH) has been widely applied in conventional emulsion polymerization to render materials with specific chemical and physical properties. However, significant drawbacks are usually associated with the conventional process, such as the migration of low-molar-mass surfactants, and the low cross-linking efficiency due to the random distribution of the cross-linkers throughout the nanoparticles. We demonstrate here the concept of surface cross linking of latexes in a RAFT-mediated surfactant-free procedure that overcomes the migration of surfactants while improving the cross-linking efficiency of latexes. Specifically, the "surface cross linking " here refers to the cross-linking of colloidal particles' surfaces during the film formation process. First, an amphiphilic RAFT agent with the incorporation of a cross-linking unit (DAAM) was designed and synthesized; the following controlled emulsion polymerizations provide a series of surfactant-free latexes with excellent colloidal stabilities, high solid contents (> 40.0 wt %), and a size range of 150-250 nm. To access RAFT latexes with different cross-linking degrees and mechanisms, amphiphilic RAFT agents with different units of cross-linking component (DAAM) were designed and implemented for the controlled emulsion polymerization of styrene and n-butyl acrylate. Next, the surface cross linkable and randomly cross-linkable RAFT latexes and corresponding films were prepared. It was found that the surface cross-linked films exhibited not only improved Young's modulus and storage modulus but also better solvent resistance compared to the control group with DAAM units randomly distributed throughout the particle systems. Remarkably, it was noticed that the surface cross linking process can simultaneously increase the strain at break and ultimate stress, and this is the first observation of such a phenomenon in DAAM/ADH cross-linked latex films. Overall, this study represents the first attempt that combines surfactant-free RAFT-mediated emulsion polymerization with the surface cross-linking chemistry to produce cohesive films with enhanced and tunable mechanical properties. This universal synthetic strategy is applicable to a broad range of commercial monomers and can be used as a platform technology for advanced industrial applications.

The preparation of photoluminescent polymer assemblies with a wide range of morphologies, including spongosomes and cubosomes, via an efficient RAFT-mediated polymerization-induced self-assembly (RAFT-PISA) process, was demonstrated.

Chiral metallic nanoparticles can exhibit novel plasmonic circular dichroism (PCD) in the ultraviolet and visible range of the electromagnetic spectrum. Here, we investigate how thermoresponsive dielectric nanoenvironments will influence such PCD responses through poly(N-isopropylacrylamide) (PNIPAM) modified chiral gold nanorods (AuNRs). We observed the temperature-dependent chiral plasmonic responses distinctly from unmodified counterparts. As for the modified systems, the PCD peaks for both L-AuNRs and D-AuNRs at 50 °C red shifted simultaneously with enhanced intensities compared to the results at 20 °C. In contrast, the unmodified L-AuNRs and D-AuNRs exhibited no peak shift with reduced intensities. Subsequent simulation and experimental studies demonstrated that the enhanced PCD was attributed to PNIPAM chain collapse causing the increase of the refractive index by expelling minute water out of the corona surrounding chiral plasmonic AuNRs. Notably, such thermoresponsive chiral plasmonic responses are reversible, general, and extendable to other types of chiral plasmonic nanoparticles.

Polymer-metal nanocomposites are of increasing interest for a wide range of applications; however, the preparation of these nanocomposites often requires the addition of external initiation and reducing agents for the synthesis of polymer and metal nanoparticles, respectively. Herein, we demonstrate the preparation of polymer-metal nanocomposites for improved catalytic performance by utilizing ultrasound as both the initiation and reducing source. Specifically, synthesis of the macro-RAFT agent containing poly[2-(dimethylamino)ethyl methacrylate], followed by ultrasound-initiated polymerization-induced self-assembly (sono-PISA), provides triblock copolymer nanoparticles containing tertiary amine groups. These polymer nanoparticles were further used as the scaffold for the in situ reduction of metal ions (Au and Pd ions) by radicals generated via sonolysis of water without additional reducing agents. The immobilization of metal nanoparticles has been confirmed by TEM and electron diffraction patterns. Polymer-Au nanocomposites with stepwise-grown AuNPs can be applied as surface-enhanced Raman scattering (SERS) substrates for 4-aminothiophenol (4-ATP) detection. Furthermore, the catalytic performances of these prepared polymer-Au and polymer-Pd nanocomposites were examined for aerobic alcohol oxidation and the Suzuki-Miyaura cross-coupling reaction, respectively. Overall, this strategy is expected to greatly expand the utility of ultrasound in the preparation of polymer-metal nanocomposites and promote the catalytic applications of these nanocomposites.

Non-lamellar lyotropic liquid crystalline (LLC) lipid nanoparticles contain internal multidimensional nanostructures such as the inverse bicontinuous cubic and the inverse hexagonal mesophases, which can respond to external stimuli and have the potential of controlling drug release. To date, the internal LLC mesophase responsiveness of these lipid nanoparticles is largely achieved by adding ionizable small molecules to the parent lipid such as monoolein (MO), the mixture of which is then dispersed into nanoparticle suspensions by commercially available poly(ethylene oxide)–poly(propylene oxide) block copolymers. In this study, the Reversible Addition-Fragmentation chain Transfer (RAFT) technique was used to synthesize a series of novel amphiphilic block copolymers (ABCs) containing a hydrophilic poly(ethylene glycol) (PEG) block, a hydrophobic block and one or two responsive blocks, i.e., poly(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate) (PTBA) and/or poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA). High throughput small angle X-ray scattering studies demonstrated that the synthesized ABCs could simultaneously stabilize a range of LLC MO nanoparticles (vesicles, cubosomes, hexosomes, inverse micelles) and provide internal particle nanostructure responsiveness to changes of hydrogen peroxide (H2O2) concentrations, pH and temperature. It was found that the novel functional ABCs can substitute for the commercial polymer stabilizer and the ionizable additive in the formation of next generation non-lamellar lipid nanoparticles. These novel formulations have the potential to control drug release in the tumor microenvironment with endogenous H2O2 and acidic pH conditions.

Tissues, which consist of groups of closely packed cell arrays, are essentially sheet-like biosynthesis plants. In tissues, individual cells are discrete microreactors working under highly viscous and confined environments. Herein, soft polystyrene-encased nanoframe (PEN) reactor arrays, as analogous nanoscale "sheet-like chemosynthesis plants", for the controlled synthesis of novel nanocrystals, are reported. Although the soft polystyrene (PS) is only 3 nm thick, it is elastic, robust, and permeable to aqueous solutes, while significantly slowing down their diffusion. PEN-associated palladium (Pd) crystallization follows a diffusion-controlled zero-order kinetics rather than a reaction-controlled first-order kinetics in bulk solution. Each individual PEN reactor has a volume in the zeptoliter range, which offers a unique confined environment, enabling a directional inward crystallization, in contrast to the conventional outward nucleation/growth that occurs in an unconfined bulk solution. This strategy makes it possible to generate a set of mono-, bi-, and trimetallic, and even semiconductor nanocrystals with tunable interior structures, which are difficult to achieve with normal systems based on bulk solutions.

Polymer/graphene oxide (GO) composites, which combine the physical properties of GO and the processability of polymers, are of increasing interest in a variety of applications ranging from conductive foams, sensors, to bioelectronics. However, the preparation of these composites through physical blending demands the polymers with functional groups that interact strongly with the GO. Here the design and synthesis of a new bifunctional reversible addition-fragmentation chain transfer (RAFT) agent are demonstrated, which allows the synthesis of polymers with predetermined molecular weights and low dispersibilities (Ð), while having functionalities at both polymer termini that allow strong binding to GO. To access polymers with diverse thermal and mechanical properties, acrylonitrile-styrene-acrylate (ASA) copolymers with different types of acrylates, both short and long side chains, are synthesized under the control of the bifunctional RAFT agent. Furthermore, the strong binding between GO and the synthesized polymers is verified and explored to prepare polymer/GO composites with diverse tensile strengths and conductivity in the range of semiconductors. Overall, this novel RAFT agent is expected to expand the utility of polymer/GO composites by providing well-defined polymers with tunable properties and strong binding with GO.

We herein report a facile strategy to prepare triggered degradable block copolymer nano/macro-objects, ranging from typical micelles, worms, jellyfish, and vesicles to rarely achieved spongosomes, cubosomes, and hexosomes via RAFT-mediated polymerization-induced self-assembly (PISA). The morphological transitions from a simple spherical micelle to a spongosome, ordered Im3¯m cubosome, and p6mm hexosome were captured and demonstrated by TEM, SEM, and synchrotron SAXS. In addition, morphological phase diagrams including important factors, such as solid contents, degree of polymerization (DP), and stabilizer block chain length, were constructed to unveil the formation mechanism and guide the scalable preparation of complex morphologies with packing parameter (P) > 1. This study not only represents an example that achieved inverse mesophases via acrylate-based monomers with high conversion but also reports a triggered degradable system in the most extended morphological range via PISA. The facile synthesis and stimuli-responsiveness of our system should greatly expand the utility of polymer inverse mesophases for triggered releasing, templating, and many other applications.

The proper design and selection of RAFT agents allow the preparation of eutectic gallium–indium (EGaIn) based liquid metal nanoparticles with grafted polymers.

The nanoscale hierarchical design that draws inspiration from nature's biomaterials allows the enhancement of material performance and enables multifarious applications. Self-assembly of block copolymers represents one of these artificial techniques that provide an elegant bottom-up strategy for the synthesis of soft colloidal hierarchies. Fast-growing polymerization-induced self-assembly (PISA) renders a one-step process for the polymer synthesis and in situ self-assembly at high concentrations. Nevertheless, it is exceedingly challenging for the fabrication of hierarchical colloids via aqueous PISA, simply because most monomers produce kinetically trapped spheres except for a few PISA-suitable monomers. We demonstrate here a sequential one-pot synthesis of hierarchically self-assembled polymer colloids with diverse morphologies via aqueous PISA that overcomes the limitation. Complex formation of water-immiscible monomers with cyclodextrin via "host-guest" inclusion, followed by sequential aqueous polymerization, provides a linear triblock terpolymer that can in situ self-assemble into hierarchical nanostructures. To access polymer colloids with different morphologies, three types of linear triblock terpolymers were synthesized through this methodology, which allows the preparation of AXn-type colloidal molecules (CMs), core-shell-corona micelles, and raspberry-like nanoparticles. Furthermore, the phase separations between polymer blocks in nanostructures were revealed by transmission electron microscopy and atomic force microscopy-infrared spectroscopy. The proposed mechanism explained how the interfacial tensions and glass transition temperatures of the core-forming blocks affect the morphologies. Overall, this study provides a scalable method of the production of CMs and other hierarchical structures. It can be applied to different block copolymer formulations to enrich the complexity of morphology and enable diverse functions of nano-objects.