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Bottlebrush statistical copolymers (BSCPs) with poly(ethylene oxide) (PEO) and polystyrene (PS) side chains grafted to a polynorbornene (PNB) backbone were synthesized by ring-opening metathesis polymerization (ROMP). The impact of the glassy PS side chains on the crystallization of the PEO side chains as a function of the backbone length, grafting densities, and fraction of the PS and PEO side chains is described. The bottlebrush architecture, where the side chains are anchored to the backbone, inherently constrains the mobility of PEO. Compared with the bulk crystallization temperature of PEO, the higher glass transition temperature of PS places further constraints on PEO crystallization. The limited mobility of PEO leads to cold crystallization behavior during heating. Reduced grafting densities, in turn, reduce side-chain crowding, leading to less extended pendant structures. The degree of crystallinity of PEO was found to decrease at lower grafting densities to a point where crystallization was not observed. The average distance between bottlebrush backbones increased linearly with the backbone length, suggesting that the backbone forms a distinct mesodomain. For BSCPs with asymmetric volume fractions of PS and PEO side chains, the degree of crystallinity of PEO increases with a change from cold crystallization to normal nucleation and growth during cooling, as a result of reduced constraints on PEO mobility by the glassy PS side chains.

Amphiphilic bottlebrush block copolymers (BBCPs), having a hydrophilic bottlebrush polymer (BP) linked covalently to a hydrophobic BP, were found to segregate to liquid-liquid interfaces to minimize the free energy of the system. The key parameter influencing the outcome of the experiments is the ratio between the degree of polymerization of the backbone (NBB) and that of the side-chain brushes (NSC). Specifically, a spherical, star-like configuration results when NBB < NSC, while a cylindrical, bottlebrush-like shape is preferred when NBB > NSC. Dynamic interfacial tension (γ) and fluorescence recovery after photobleaching (FRAP) measurements show that the BBCP configuration influences the areal density and in-plane diffusion at the fluid interface. The characteristic relaxation times associated with BBCP adsorption (τA) and reorganization (τR) were determined by fitting time-dependent interfacial tension measurements to a sum of two exponential relaxation functions. Both τA and τR initially increased with NBB up to 92 repeat units, due to the larger hydrodynamic radius in solution and slower in-plane diffusivity, attributed to a shorter cross-sectional diameter of the side-chains near the block junction. This trend reversed at NBB = 190, with shorter τA and τR attributed to increased segregation strength and exposure of the bare water/toluene interface due to tilting and/or wiggling of the backbone chains, respectively. The adsorption energy barrier decreased with higher NBB, due to a reduced BBCP packing density at the fluid interface. This study provides fundamental insights into macromolecular assembly at fluid interfaces, as it pertains to unique bottlebrush block architectures.

Conventional ligands for CsPbBr3 perovskite nanocrystals (NCs), composed of polar, coordinating head groups (e.g., ammonium or zwitterionic) and aliphatic tails, are instrumental in stabilizing the NCs against sintering and aggregation. Nonetheless, the aliphatic (insulating) nature of these ligands represents drawbacks with respect to objectives in optoelectronics, and yet removing these ligands typically leads to a loss of colloidal stability. In this paper, we describe the preparation of CsPbBr3 NCs in the presence of discrete conjugated oligomers that were prepared by an iterative synthetic approach and capped at their chain ends with sulfobetaine zwitterions for perovskite coordination. Notably, these zwitterionic oligofluorenes are compatible with the hot injection and ligand exchange conditions used to prepare CsPbBr3 NCs, yielding stable NC dispersions with high photoluminescence quantum yields (PLQY, >90%) and spectral features representative of both the perovskite core and conjugated ligand shell. Controlling the chain length of these capping ligands effectively regulated inter-NC spacing and packing geometry when cast into solid films, with evidence derived from both transmission electron microscopy (TEM) and grazing incidence X-ray scattering measurements.

The phase behavior of block copolymers (BCPs) at the water-oil interface is influenced by the segmental interaction parameter ( χ${\chi }$ ) and chain architecture. We synthesized a series of star block copolymers (s-BCPs) having polystyrene (PS) as core and poly(2-vinylpyridine) (P2VP) as corona. The interaction parameters of block-block ( χ${\chi }$ PS-P2VP ) and block-solvent ( χ${\chi }$ P2VP-solvent ) were varied by adjusting the pH of the aqueous solution. Lowering pH increased the fraction of quaternized-P2VP (Q-P2VP) with enhanced hydrophilicity. By transferring the equilibrated interfacial assemblies, morphologies ranging from bicontinuous films at pH of 7 and 3.1 to nanoporous and nanotubular structure at pH of 0.65 were observed. The nanoporous films formed hexagonally packed pores in s-BCP matrix, while nanotubes comprised Q-P2VP as corona and PS as core. Control over pore size, d-spacing between pores, and nanotube diameters was achieved by varying polymer concentration, molecular weight, volume fraction and arm number of s-BCPs. Large-scale nanoporous films were obtained by freeze-drying emulsions. Remarkably, the morphologies of linear BCPs were inverted, forming hexagonal-packed rigid spherical micelles with Q-P2VP as core and PS as corona in multilayer. This work provides insights of phase behaviors of BCP at fluids interface and offer a facile approach to prepare nanoporous film with well-controlled pore structure.

Bottlebrush random copolymers (BRCPs), consisting of a random distribution of two homopolymer chains along a backbone, can segregate to the interface between two immiscible homopolymers. BRCPs undergo a reconfiguration, where each block segregates to one of the homopolymer phases, adopting a Janus-type structure, reducing the interfacial tension and promoting adhesion between the two homopolymers, thereby serving as a Janus bottlebrush copolymer (JBCP) compatibilizer. We synthesized a series of JBCPs by copolymerizing deuterated or hydrogenated polystyrene (DPS/PS) and poly(tert-butyl acrylate) (PtBA) macromonomers using ruthenium benzylidene-initiated ring-opening metathesis polymerization (ROMP). Subsequent acid-catalyzed hydrolysis converted the PtBA brushes to poly(acrylic acid) (PAA). The JBCPs were then placed at the interface between DPS/PS homopolymers and poly(2-vinyl pyridine) (P2VP) homopolymers, where the degree of polymerization of the backbone (NBB) and the grafting density (GD) of the JBCPs were varied. Neutron reflectivity (NR) was used to determine the interfacial width and segmental density distributions (including PS homopolymer, PS block, PAA block and P2VP homopolymer) across the polymer-polymer interface. Our findings indicate that the star-like JBCP with NBB = 6 produces the largest interfacial broadening. Increasing NBB to 100 (rod-like shape) and 250 (worm-like shape) reduced the interfacial broadening due to a decrease in the interactions between blocks and homopolymers by stretching of blocks. Decreasing the GD from 100% to 80% at NBB = 100 caused an increase the interfacial width, yet further decreasing the GD to 50% and 20% reduced the interfacial width, as 80% of GD may efficiently increase the flexibility of blocks and promote interactions between homopolymers, while maintaining relatively high number of blocks attached to one molecule. The interfacial conformation of JBCPs was further translated into compatibilization efficiency. Thin film morphology studies showed that only the lower NBB values (NBB = 6 and NBB = 24) and the 80% GD of NBB = 100 had bicontinuous morphologies, due to a sufficient binding energy that arrested phase separation, supported by mechanical testing using asymmetric double cantilever beam (ADCB) tests. These provide fundamental insights into the assembly behavior of JBCPs compatibilizers at homopolymer interfaces, opening strategies for the design of new BCP compatibilizers.

The self-assembly of high-χ low-N block copolymers (BCPs) can give patterns with sub-10 nm full pitch, serving as a promising alternative to photolithographic methods. In this work, we synthesized poly(solketal methacrylate)-block-polystyrene copolymers, PSM-b-PS, with various volume ratios of the two blocks. After hydrolysis of the PSM block into poly(glycerol monomethacrylate), PGM, the BCPs had both lamellar and cylindrical microdomain morphologies in the bulk phase and in thin films. In addition to our previously developed solid-state hydrolysis strategy involving trifluoroacetic acid vapor, we developed a new photoinduced solid-state hydrolysis using photoacid generators, PAGs, embedded within the polymer films. After exposure to UV followed by a postexposure baking or solvent vapor annealing, the BCPs transitioned from the disordered, phase-mixed state into laterally ordered cylindrical patterns. In comparison to linear BCPs that rely on a random copolymer layer to modify interfacial interactions with the substrate to promote an orientation of the microdomains normal to the interface, we found that the microdomains in bottlebrush multiblock copolymers oriented normal to the interface absent substrate modification due to the chain architecture.

Star block copolymers (s-BCPs), comprised of multiple linear diblock copolymers joined at a central point, are shown to segregate to the interface between two immiscible homopolymers that are identical to the blocks of the s-BCPs. The s-BCPs undergo a configurational transition at the interface, with different blocks of copolymers being embedded in their respective homopolymers, thereby bridging the interface and promoting adhesion. A series of 4-arm s-BCPs were synthesized with hydrogenated or deuterated polystyrene (PS/dPS) as the core block and poly(2-vinylpyridine) (P2VP) as the corona block, which was directly placed at the interface between the two homopolymers. Neutron reflectivity (NR) was used to determine the concentration profiles of the PS homopolymer, s-BCP core blocks, and P2VP total segments under equilibrium. The investigation varies the molecular weight (MW) and the total number of s-BCPs at the interface. Self-consistent-field theory (SCFT) was also employed to calculate the concentration profiles of the components at the interface, which were in excellent agreement with experimental results. The NR showed that the interfacial width between the homopolymers increased with the increasing number of s-BCPs at the interface up to a saturation limit. Beyond this limit, additional s-BCPs were released into the corona-miscible phase as unimolecular micelles. For a comparable interlayer thickness of s-BCPs at the interface, lower MW s-BCPs generated a broader interface. SCFT analysis suggested that, at the same packing density, the arms of the low MW s-BCPs align more parallel to the interface, while the arms of high MW s-BCPs adopt a more normal orientation, like their linear BCP counterparts. Furthermore, it was also observed that the core blocks, constrained by the junction points, were oriented more parallel and closer to the interface than the corona blocks. The phase behavior of the polymer blends revealed that s-BCP additives can efficiently reduce the domain size, with the low MW yielding smaller domain sizes due to the greater reduction in the interfacial energy and the high MW arresting phase separation due to their higher binding energy and a jamming of the interfacial assemblies. Asymmetric double cantilever beam (ADCB) tests demonstrated that s-BCPs promoted adhesion more efficiently than their linear BCP counterparts due to stronger binding energy per molecule, suggesting a more efficient compatibilizer for polymer upcycling. The results from these studies provide fundamental insights into the assembly of s-BCPs at homopolymer interfaces, the reduction of domain size, and promotion of adhesion, providing a strategy for the use of s-BCPs as stealth surfactants and universal compatibilizers.

Emulsions have wide applications in the food, cosmetics, and pharmaceutical industries. Emulsions stabilized with polymers having different architectures, such as linear diblock and triblock copolymers, branched polymers, star polymers, graft polymers, and densely grafted bottlebrush polymers, have been used for encapsulation, delivery, and as templates for polymerization reactions. Stimuli-responsive polymers have been used for on-demand demulsification and emulsion engineering. In this review, we highlight the developments in the past decade that used polymers with advanced architectures as multi-functional emulsifiers.

We describe a fully open‐sourced Python package to process raw X‐ray scattering data using a GANESHA SAXSLAB facility, and review in this manuscript the connection of X‐ray scattering theories with the open‐sourced package. This package affords researchers more flexibility in analyzing and visualizing X‐ray scattering and reflectivity data from what is now a commonplace facility at many universities and research laboratories engaged in polymer research. We briefly review the applications of X‐ray scattering and diffraction, followed by the scattering theories. A pedagogical introduction to processing X‐ray scattering data is provided using the modules in the Python package. We compare conventions to visualize and interpret transmission and grazing‐incidence scattering data using self‐assembled lamellar morphology of bottlebrush copolymers as an example, then describe how area detectors measure specular and off‐specular reflectivity. Examples of in‐house reflectivity and grazing incidence scattering for the metrological examination of a grating are provided, where the full pitch and pitch height of a line pattern is measured easily without needing to simulate the full scattering intensity profile. [ABSTRACT FROM AUTHOR]

As a class of semiconductor nanocrystals that exhibit high photoluminescence quantum yield (PLQY) at tunable wavelengths, perovskite nanocrystals (PNCs) are attractive candidates for optoelectronic and light‐emitting devices. However, attempts to optimize PNC integration into such applications suffer from PNC instability and loss of PL over time. Here, we describe the impact of organic and polymeric N‐oxides when used in conjunction with PNCs, whereby a significant increase in PNC quantum yield is observed in solution, and stable PL emission is obtained in polymeric nanocomposites. Specifically, when using aliphatic N‐oxides in ligand exchange with CsPbBr3 PNCs in solution, a substantial boost in PNC brightness is observed (~40% or more PLQY increase), followed by an alteration of the perovskite chemistry. When N‐oxide substituents are positioned pendent to a poly(n‐butyl methacrylate) backbone, the optically clear flexible nanocomposite films obtained have bright PL emission and maintain optical clarity for months. X‐ray diffraction is useful for characterizing the PNC crystalline structure following exposure to aliphatic N‐oxides, while electron microscopy (EM) and small‐angle X‐ray scattering (SAXS) measurements of the PNC‐polymer nanocomposites show this polymeric N‐oxide platform to cleanly disperse PNCs in flexible polymer films. [ABSTRACT FROM AUTHOR]

Oligometastatic prostate cancer is a term that is most often used to refer to limited sites of disseminated tumor growth following primary radical prostatectomy (RP) or radiotherapy (RT), while de novo oligometastatic is a term that is used to refer to prostate tumors that have disseminated to limited sites before definitive treatment. In patients with de novo oligometastatic prostate cancer, treatment planning must thus consider the need to manage the primary tumor and the associated distant lesions. Traditionally, resectioning primary metastatic tumors is not thought to offer significant benefits to affected patients while increasing their risk of surgery-related complications. Recent clinical evidence indicates that patients undergoing cytoreductive prostatectomy (CRP) may observe substantial enhancements in overall survival rates while not experiencing a noticeable decline in their quality of life. Nevertheless, based on the current body of evidence, it is deemed inadequate to justify revising clinical guidelines. Consequently, it is not advisable to propose CRP for patients with oligometastatic prostate cancer. The present review was compiled to summarize available data regarding the indications, functional outcomes, and oncological outcomes associated with cytoreductive radical prostatectomy to provide a robust and objective foundation that can be used to better assess the value of this interventional strategy from a clinical perspective. [ABSTRACT FROM AUTHOR]

Castration-resistant prostate cancer (CRPC) treatment still remains difficult. The aim of the present study was to determine the antitumour efficacy of the MutT homolog 1 (MTH1) inhibitor, TH1579, against castration-resistant prostate cancer. PC-3 and DU-145 prostate cancer cells were treated with different concentrations of TH1579. C4-2 cells with or without androgen receptor (AR) were also treated with TH1579 to assess AR function. Cell survival, 8-oxo-dG levels and DNA damage were measured using cell viability assays, western blotting, immunofluorescence analysis and flow cytometry. TH1579 inhibited CRPC cell proliferation in a dose-dependent manner. The viabilities of PC-3 and DU-145 cells treated with 1 µM of TH1579 were 28.6 and 24.1%, respectively. The viabilities of C4-2 cells with and without AR treated with 1 µM TH1579 were 10.6 and 19.0%, respectively. Moreover, TH1579 treatment increased 8-oxo-dG levels, as well as the number of 53BP1 and γH2A.X foci, resulting in increased DNA double-strand breakage and apoptosis in PC-3 and DU-145 cells. The findings of the present study demonstrated that TH1579 exerted strong antitumour effects on CRPC cells, and may therefore be used as a potential therapeutic agent for the clinical treatment of CRPC. [ABSTRACT FROM AUTHOR]

KAP1 is a universal corepressor for Kruppel-associated box zinc finger proteins. In this study, expression level of KAP1 and its association with drug resistance and expression of P-gp and BCRP in epithelial ovarian cancer were investigated. Immunohistological staining of KAP1 in cancer and matched paraneoplastic tissues was evaluated in 242 patients with epithelial ovarian cancer. Immunohistological staining of P-gp and BCRP were also evaluated, and the associations with the expression of KAP1 in epithelial ovarian cancer were investigated. MTT assay for cell proliferation and clonogenic survival assay were applied to determine the effect of KAP1 on the sensitivity of DDP, through up-regulating the level of KAP1 expression of SKOV3 using KAP1 plasmid and down-regulating the level of KAP1 expression of SKOV3/DDP using siRNA. The results demonstrated that the expression levels of KAP1 in cancer tissues were higher than matched paraneoplastic tissues (t = 21.39, P<0.001). The patients with higher KAP1 expression often had drug resistance, and the level of KAP1 expression was positively correlated with the expression of P-gp and BCRP (P = 0.07 and P<0.001 respectively). Up-regulated the expression of KAP1 in SKOV3 cell line induced the up-regulated expression of BCRP and P-gp, increasing the resistance of chemotherapeutic drug, and down-regulated the expression of KAP1 got opposite effects. KAP1 expression correlated with aggressive clinical features in ovarian cancer, maybe through regulating the expression of P-gp and BCRP.