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With the aid of the concept of macromolecular engineering, this work proposes mixtures of A(AB)n miktoarm star copolymers and nanoparticles to obtain bicontinuous gyroid nanostructures with high loading of functionalized nanoparticles.

Sleep can affect nonalcoholic fatty liver disease (NAFLD). We investigated the association between sleep duration, sleep quality, and NAFLD. From January to December 2018, 1,073 patients (age: 37.94 ± 10.88, Body Mass Index (BMI): 22.85 ± 3.27) were enrolled. Pittsburgh Sleep Quality Index Questionnaire and Munich Chronotype Questionnaire were used to assess sleep duration, quality, and habits. Ultrasonography was used to diagnose NAFLD. Multivariate logistic regression models were used to calculate the odds ratio (OR) and 95% confidence interval (CI) of the risk of NAFLD by different types of sleep duration and sleep quality. No significant differences in sleep time, sleep quality, and sleep habits between the NAFLD and the non-NAFLD groups were observed (P > 0.05). There was no correlation between sleep duration and NAFLD in the whole cohort. After adjusting for age, exercise, fasting plasma glucose, and BMI, the group with long sleep duration showed a decreased risk of NAFLD in men (OR = 0.01, 95% CI: 0.001–0.27, P = 0.032). However, in all four adjusted models, no correlation between sleep duration, quality, and NAFLD was found in women. In conclusion, sleep duration was significantly and negatively associated with NAFLD in men but not women. Prospective studies are required to confirm this association.

Hua Ye,1 Mengxia Sun,2 Shiliang Huang,1 Feng Xu,1 Jian Wang,3 Huiwei Liu,1 Liangshun Zhang,1 Wenjing Luo,1 Wenying Guo,1 Zhe Wu,1 Jie Zhu,4 Hong Li4 1Department of Gastroenterology, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of China; 2Department of Clinical Medicine, Medical School of Ningbo University, Ningbo, Zhejiang, 315211, People’s Republic of China; 3Department of Dermatology, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of China; 4Department of Hepatobiliary Surgery, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of ChinaCorrespondence: Hua YeDepartment of Gastroenterology, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of ChinaTel/Fax +86 57483023687Email yh-med@163.comHong LiDepartment of Hepatobiliary Surgery, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of ChinaEmail lancet2017@163.comBackground: Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. HCC transcriptome has been extensively studied; however, the progress in disease mechanisms, prognosis, and treatment is still slow.Methods: A rank-based module-centric workflow was introduced to analyze important modules associated with HCC development, prognosis, and drug resistance. The currently largest HCC cell line RNA-Seq dataset from the LIMORE database was used to construct the reference modules by weighted gene co-expression network analysis.Results: Thirteen reference modules were identified with validated reproducibility. These modules were all associated with specific biological functions. Differentially expressed module analysis revealed the crucial modules during HCC development. Modules and hub genes are indicative of patient survival. Modules can differentiate patients in different HCC stages. Furthermore, drug resistance was revealed by drug-module association analysis. Based on differentially expressed modules and hub genes, six candidate drugs were screened. The hub genes of those modules merit further investigation.Conclusion: We proposed a reference module-based analysis of the HCC transcriptome. The identified modules are associated with HCC development, survival, and drug resistance. M3 and M6 may play important roles during HCV to HCC development. M1, M3, M5, and M7 are associated with HCC survival. High M4, high M9, low M1, and low M3 may be associated with dasatinib, doxorubicin, CD532, and simvastatin resistance. Our analysis provides useful information for HCC diagnosis and treatment.Keywords: HCV, IC50, microarray, module preservation, WGCNA

Background Insufficient sleep and circadian rhythm disruption may cause cancer, obesity, cardiovascular disease, and cognitive impairment. The underlying mechanisms need to be elucidated. Method Weighted gene co-expression network analysis (WGCNA) was used to identify co-expressed modules. Connectivity Map tool was used to identify candidate drugs based on top connected genes. R ptestg package was utilized to detected module rhythmicity alteration. A hypergeometric test was used to test the enrichment of insomnia SNP signals in modules. Google Scholar was used to validate the modules and hub genes by literature. Results We identified a total of 45 co-expressed modules. These modules were stable and preserved. Eight modules were correlated with sleep restriction duration. Module rhythmicity was disrupted in sleep restriction subjects. Hub genes that involve in insufficient sleep also play important roles in sleep disorders. Insomnia GWAS signals were enriched in six modules. Finally, eight drugs associated with sleep disorders were identified. Conclusion Systems biology method was used to identify sleep-related modules, hub genes, and candidate drugs. Module rhythmicity was altered in sleep insufficient subjects. Thiamphenicol, lisuride, timolol, and piretanide are novel candidates for sleep disorders.

Programmable coassembly of multicomponent nanoparticles (NPs) into heterostructures has the capability to build upon nanostructured metamaterials with enhanced complexity and diversity. However, a general understanding of how to manipulate the sequence-defined heterostructures using straightforward concepts and quantitatively predict the coassembly process remains unreached. Drawing inspiration from the synthetic concepts of molecular block copolymers is extremely beneficial to achieve controllable coassembly of NPs and access mesoscale structuring mechanisms. We herein report a general paradigm of kinetic pathway guidance for the controllable coassembly of bivalent DNA-functionalized NPs into regular block-copolymer-like heterostructures

Directing nanoparticles into ordered organization in polymer matrix to improve macroscopic properties of nanocomposites remains a challenge. Herein, by means of theoretical simulations, we show the high permittivity of hybrid nanostructures designed with mixtures of AB block copolymer-grafted nanoparticles and lamella-forming AC diblock copolymers. The grafted nanoparticles self-assemble into parallel stripes or highly ordered networks in the lamellae of the AC diblock copolymers. The ordered nanoparticle networks, including honeycomb-like and kagome networks, provide bending and conductive pathways for concentrating electric fields, which results in the improvement of the permittivity. We envisage that this strategy will open a gateway to prepare hierarchically ordered functional nanocomposites with distinctive dielectric properties.

Antibacterial hydrogels have received intensive interest in soft tissue repair, especially for preventing infections associated with impaired wound healing. However, developing an inherent antibacterial hydrogel dressing with antifouling ability without causing secondary damage to repaired tissues has proven to be promising and challenging. In this work, a mussel-inspired zwitterionic sulfobetaine acrylamide hydrogel incorporated with laponite (LAP) nanoplatelets and methacrylamide dopamine (DMA) has been developed for effective wound dressings, where LAP nanoplatelets and DMA endow the hydrogel with enhanced mechanical strength and substance adhesiveness, respectively. Moreover, LAP nanoplatelets could immobilize hydrophobic curcumin to form complexes, realizing the controlled release of curcumin to provide antimicrobial activities. In vitro results showed that hydrogels did not cause obvious cytotoxicity and hemolysis, but they still can well resist bovine serum albumin (BSA) adsorption. Wound closure and histopathological experiments have been performed in vivo to evaluate the therapeutic effects of the hydrogel by a full-thickness skin defect mouse model, and the results demonstrated that infected wounds could be well closed after being treated with the hydrogel for 15 days. Meanwhile, the full re-epithelialization and total formation of new connective tissues can be clearly observed by histological analysis. Moreover, the hydrogel could be easily removed from recovered tissues without causing secondary damage. Therefore, this antifouling and antimicrobial hydrogel dressing with suitable adhesiveness would provide a new strategy for wound healing without causing secondary damage.

Precise organization of nanoparticles (NPs) into regularly well-defined arrays represents a continuing challenge in the development of high-performance metamaterials. Herein, zone-annealed diblock ...

Bacterial infection, especially multidrug-resistant (MDR) bacterial infection has threatened public health drastically. Here, we fabricate an “acid-triggered” nanoplatform for enhanced photodynamic antibacterial activity by reducing the aggregation of photosensitizers (PSs) in bacterial acidic microenvironment. Specifically, a functional amphiphilic block copolymer was first synthesized by using a pH-sensitive monomer, 2-(diisopropylamino) ethyl methacrylate (DPA) and porphyrin-based methacrylate (TPPC6MA) with poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) as the macromolecular chain transfer agent, and POEGMA-b-[PDPA-co-PTPPC6MA] block copolymer was further self-assembled into spherical nanoparticles (PDPA-TPP). PDPA-TPP nanoparticles possess an effective electrostatic adherence to negatively charged bacterial cell membrane, since they could rapidly achieve positive charge in acidic bacterial media. Meanwhile, the acid-triggered dissociation of PDPA-TPP nanoparticles could reduce the aggregation caused quenching (ACQ) of the photosensitizers, leading to around 5 folds increase of the singlet oxygen (1O2) quantum yield. In vitro results demonstrated that the “acid-triggered” PDPA-TPP nanoparticles could kill most of MDR S. aureus (Gram-positive) and MDR E. coli (Gram-negative) by enhanced photodynamic therapy, and they could resist wound infection and accelerate wound healing effectively in vivo. Furthermore, PDPA-TPP nanoparticles could well disperse the biofilm and almost kill all the biofilm-containing bacteria. Thus, by making use of the bacterial acidic microenvironment, this “acid-triggered” nanoplatform in situ will open a new path to solve the aggregation of photosensitizers for combating broad-spectrum drug-resistant bacterial infection.

Increasing the excess free energy (ΔFd) and lowering the free-energy barrier (ΔFb) of a defect are very critical for the preparation of defect-free ordered structures from the self-assembly of bloc...

Bacterial infection and biofilms cause non-healing chronic wounds and threaten human health. Although antibiotics still play an irreplaceable role to treat infectious diseases in clinics, increasing attention has been paid to the problem of multidrug resistance (MDR). As a novel strategy to deal with bacterial infection, photodynamic antimicrobial therapy (PDAT) has shown promising potential to reduce bacterial infection, and stimuli-responsive nanomaterials have been shown to enhance the antibacterial efficiency and postpone the emergence of drug-resistant bacteria. In this work, we developed a bacterial microenvironment-responsive nanoplatform to eliminate bacteria and bacterial biofilms under 650 nm laser irradiation. Reversible addition-fragmentation chain transfer (RAFT) polymerization was applied to synthesize an H2O2 responsive block copolymer of POEGMA-b-PBMA, and the antibacterial drug of porphyrin TAPP was loaded to form nanoparticles (PT) by a co-assembled approach. At the infection area with overexpressed peroxide, nanoparticles were disintegrated due to the cleaved boronic ester leading to the release of TAPP. Furthermore, the released TAPP became protonated in the acidic infection area (pH = 5.5) and then enhanced its photodynamic antibacterial efficacy by producing higher singlet oxygen (1O2) levels under light irradiation. Both in vitro and in vivo antimicrobial and biofilm elimination experiments demonstrated that the responsive nanoplatform combined with PDAT has tremendous potential for the treatment of infections.

Self-assembly behaviors of cylinder-forming diblock copolymers directed by an array of anisotropic nanoposts with elliptical shape are explored by large cell simulations of self-consistent field theory. The strategy using elliptical nanoposts allows us to generate long-range order cylinders with single orientation by suppressing other selections of cylinder alignment. The anisotropy of nanoposts plays a significant role in improving the tolerance of commensurability conditions between the dimensions of nanopost lattices and the period of cylinders. Moreover, the local defect structures could be regulated through varying the spacing and orientation of elliptical nanoposts. This work may provide useful guidelines for designing the topographical templates and lay the groundwork for fabricating well-ordered nanostructures of block copolymer lithography.

Equilibrium phase diagrams serve as blueprints for rational design of nanostructured materials of block copolymers, but their construction is time-consuming and requires profound expertise. Herein, by virtue of the knowledge of self-consistent field theory (SCFT), the active-learning method is developed to autonomously construct the phase diagrams of block copolymers. Without human intervention, the SCFT-assisted active-learning method can rapidly search the undetected phases and efficiently reproduce the complicated phase diagrams of diblock copolymers and multiblock terpolymers via decreasing the number of sampling points to about 20%. It is clearly demonstrated that the combined uncertainty sampling/random selection scheme in the active-learning method shows the outperformance in spite of a small amount of initial data set. This work highlights the promising integration of theoretical modeling with machine learning and represents a crucial step toward rational design of nanostructured materials.

The integration of the dynamic self-consistent field theory for polymer molecules and molecular dynamics for nanoparticles is proposed to model the structural evolution of nanocomposites in the cou...

The ability to control the ordering of self-assembled nanostructures is important for block copolymer (BCP) nanotechnology but remains a challenge. Herein, we proposed a facile and feasible approach to generate ordered surface nanostructures via the self-assembly of rod-coil BCPs on a substrate. Micrometer-scale, well-aligned, and vertically orientated stripe nanopatterns are readily constructed on the substrate in a fast and controllable way. The feature sizes of the nanopatterns can be adjusted by the molecular weight of BCPs. In addition, self-assembling conditions such as BCP concentration and temperature were found to possess a significant influence on the surface morphology, as well as the order degree of the nanopatterns. Dissipative particle dynamics theoretical simulations provided complementary information for the experimental observations, including the inner chain packing and the dynamic process of the formation of ordered structures. This work presents a novel and effective strategy for the fabrication of well-aligned nanopatterns as an alternative to traditional methods.

Bacterial infection and biofilms cause non-healing chronic wounds and threaten human health. Although antibiotics still play an irreplaceable role to treat infectious diseases in clinics, increasing attention has been paid to the problem of multidrug resistance (MDR). As a novel strategy to deal with bacterial infection, photodynamic antimicrobial therapy (PDAT) has shown promising potential to reduce bacterial infection, and stimuli-responsive nanomaterials have been shown to enhance the antibacterial efficiency and postpone the emergence of drug-resistant bacteria. In this work, we developed a bacterial microenvironment-responsive nanoplatform to eliminate bacteria and bacterial biofilms under 650 nm laser irradiation. Reversible addition-fragmentation chain transfer (RAFT) polymerization was applied to synthesize an H2O2 responsive block copolymer of POEGMA-b-PBMA, and the antibacterial drug of porphyrin TAPP was loaded to form nanoparticles (PT) by a co-assembled approach. At the infection area with overexpressed peroxide, nanoparticles were disintegrated due to the cleaved boronic ester leading to the release of TAPP. Furthermore, the released TAPP became protonated in the acidic infection area (pH = 5.5) and then enhanced its photodynamic antibacterial efficacy by producing higher singlet oxygen (1O2) levels under light irradiation. Both in vitro and in vivo antimicrobial and biofilm elimination experiments demonstrated that the responsive nanoplatform combined with PDAT has tremendous potential for the treatment of infections.

Supramolecular polymerization of nanoscale particles has been considered as an effective route to prepare hierarchical nanostructures with controlled geometry and functions. However, so far, less i...

An ordered surface nanostructure endows materials advanced functions. However, fabricating ordered surface-patterned particles via the polymer self-assembly approach is a challenge. Here we report that poly(γ-benzyl-l-glutamate)-block-poly(ethylene glycol) rod-coil block copolymers are able to form uniform-surface micelles on polystyrene microspheres through a solution self-assembly approach. The size of the surface micelles can be varied by the molecular weight of the block copolymers. These surface micelles are arranged in a manner consistent with the Euler theorem. Most of the micelles are six-fold coordinated, and the number difference between the five-fold and the seven-fold coordination is 12. Simulations on model systems qualitatively reproduced the experimental findings and provided direct observations for the surface-patterned particles, including the polymer chain packing manner in surface micelles at the molecular level and the array feature of the surface micelles through 2D projections of the surface patterns.

A similarity between the polymerization reaction of molecules and the self-assembly of nanoparticles provides a unique way to reliably predict structural characteristics of nanoparticle ensembles. However, the quantitative elucidation of programmable self-assembly kinetics of DNA-encoded nanoparticles is still challenging due to the existence of hybridization and dehybridization of DNA strands. Herein, a joint theoretical-computational method is developed to explicate the mechanism and kinetics of programmable self-assembly of limited-valence nanoparticles with surface encoding of complementary DNA strands. It is revealed that the DNA-encoded nanoparticles are programmed to form a diverse range of self-assembled superstructures with complex architecture, such as linear chains, sols, and gels of nanoparticles. It is theoretically demonstrated that the programmable self-assembly of DNA-encoded nanoparticles with limited valence generally obeys the kinetics and statistics of reversible step-growth polymerization originally proposed in polymer science. Furthermore, the theoretical-computational method is applied to capture the programmable self-assembly behavior of bivalent DNA-protein conjugates. The obtained results not only provide fundamental insights into the programmable self-assembly of DNA-encoded nanoparticles but also offer design rules for the DNA-programmed superstructures with elaborate architecture.

The supramolecular polymerization of micelles and nanoparticles, drawing inspiration from the classic polymer science, provides an innovative concept to elucidate the organization of nanoscopic building units into one-dimensional hierarchical structures for wider applications in biotechnology and nanoscience. In contrast to the conventional molecular polymerization, the fundamental principles, especially the kinetics, of the supramolecular polymerization are rather less understood. Herein, capitalizing on the pre-assembled triblock copolymer micelles as prototypical systems, we propose a joint experimental-theoretical framework to probe into the mechanism and kinetics of the supramolecular polymerization. It is discovered that the self-assembly of micelles is induced by the structural defects where the core is partially exposed as a result of the imperfect coverage of the corona. The self-assembly of micelles reveals some similarities to molecular step-growth polymerization. A theoretical model of the supramolecular step-growth polymerization is proposed to complement the experimental results of defect-driven self-assembly kinetics, and reveals the essential distinction between the molecular and supramolecular polymerization kinetics. Furthermore, the kinetics and manner of self-assembly can be finely tuned by regulating the structural features of building units. These findings establish a quantitative framework for the supramolecular polymerization kinetics at the nanoscopic level that can aid in designing complex architectures and intrinsic properties of emerging materials.

Block copolymer self-assembly is a promising strategy for high-performance polymer solar cells. However, the power conversion efficiencies of block-copolymer-based solar cells are still not as high as expected. Herein, by means of theoretical simulations we show a distinct improvement in the photovoltaic performance of donor–acceptor block copolymer thin films via regulating the molecular orientation. Self-assembled lamellae perpendicular to electrodes with modulated molecular orientation were obtained by applying electric fields during the block copolymer self-assembly. Our theoretical calculations indicate that compared with the general ones without external field treatment, the power conversion efficiencies of the block copolymer nanostructures with modulated molecular orientation can be improved by more than 150% with high values of short current density and fill factor. The improvement in the photovoltaic performance is ascribed to the simultaneous enhancement in exciton diffusion to donor/acceptor interfaces and charge carrier transport to electrodes. Our findings could yield guidelines for the design of photovoltaic materials with improved photovoltaic performance via control over the molecular orientation.

Janus nanoparticles (JPs), which are anisotropic nanoparticles with at least two opposite surface regions, have been demonstrated as highly efficient compatibilizers for polymer blends. However, there are still a number of open questions concerning the mechanism behind the influence of JPs on the phase separation dynamics of polymer blends. Herein, we report a counter-intuitive feature of JPs concerning their roles during spinodal decomposition (SD); that is, they promote the decomposition of unlike polymers in the early stage of SD but retard it during the late stage. This is in remarkable contrast to traditional compatibilizers such as block copolymers and homogenous nanoparticles, which impede phase separation during both stages. We further demonstrate that the unique promoting effect of JPs at early times is due to the formation of microphase-separated homopolymer-rich regions in the vicinity of opposite JP surface regions. Our findings are expected to have important implications for the phase separation behavior of JP-compatibilized polymer blends, whose morphologies and performance could be controlled by tuning the interactions between the constituent polymers and JP-based compatibilizers.

We explore the shape and internal structure of diblock copolymer (di-BCP) nanoparticles (NPs) by using the Ginzburg-Landau free-energy expansion. The self-assembly of di-BCP lamellae confined in emulsion droplets can form either ellipsoidal or onion-like NPs. The corresponding inner structure is a lamellar phase that is either perpendicular to the long axis of the ellipsoids (L$_\perp$) or forms a multi-layer concentric shell (C$_\parallel$), respectively. We focus on the effects of the interaction parameter between the A/B monomers $\tau$, and the polymer/solvent $\chi$, as well as the NP size on the nanoparticle shape and internal morphology. The aspect ratio ($l_{\rm AR}$) defined as the length ratio between the long and short axes is used to characterize the overall NP shape. Our results show that for the solvent that is neutral towards the two blocks, as $\tau$ increases, the $l_{\rm AR}$ of the NP first increases and then decreases, indicating that the NP becomes more elongated and then changes to a spherical NP. Likewise, decreasing $\chi$ or increasing the NP size can result in a more elongated NP. However, when the solvent has a preference towards the A or B blocks, the NP shape changes from striped ellipsoid to onion-like sphere by increasing the A/B preference parameter strength. The critical condition of the transition from an L$_\perp$ to C$_\parallel$ phase has been identified. Our results are in good agreement with previous experiments, and some of our predictions could be tested in future experiments.

Directing nanoparticles into ordered organization in polymer matrix to improve macroscopic properties of nanocomposites remains a challenge. Herein, by means of theoretical simulations, we show the high permittivity of hybrid nanostructures designed with mixtures of AB block copolymer-grafted nanoparticles and lamella-forming AC diblock copolymers. The grafted nanoparticles self-assemble into parallel stripes or highly ordered networks in the lamellae of the AC diblock copolymers. The ordered nanoparticle networks, including honeycomb-like and kagomé networks, provide bending and conductive pathways for concentrating electric fields, which results in the improvement of the permittivity. We envisage that this strategy will open a gateway to prepare hierarchically ordered functional nanocomposites with distinctive dielectric properties.

In recent years, the self-assembly of copolymer micelles has become an appealing frontier of supramolecular chemistry as a strategy to construct superstructures with multiple levels of complexity. The assembly of copolymer micelles is a form of higher-level self-assembly occurring at the nanoscale level where the building blocks are preassembled micelles. Compared to one-step hierarchical self-assembly, this assembly strategy is superior for manipulating multilevel architectures because the structures of the building blocks and higher-order hierarchies can be regulated separately in the first and higher-level assembly, respectively. However, despite the substantial advances in the self-assembly of copolymer micelles in recent years, universal laws have not been comprehensively summarized. This review article aims to provide an overview of the current progress and developing prospects of the self-assembly of copolymer micelles. In particular, the significant role of theoretical simulations in revealing the mechanism of copolymer micelle self-assembly is discussed.

Uniform toroidal micelles can be constructed via the supramolecular cyclization of semiflexible cylindrical micelles, but revealing the conditions under which the cyclization occurs and the mechanism underlying the cyclization remains a challenge. In this study, we performed Brownian dynamics simulations of the supramolecular cyclization of semiflexible cylindrical micelles formed by rod-coil graft copolymers to obtain the cyclization conditions and understand the cyclization mechanism. It was found that the balance of the bending energy of the polymer backbones with the self-attraction energy between the pendant groups on the polymer backbones plays an important role in the cyclization process. A theoretical model based on this balance is developed to explain the cyclization mechanism, and the conditions required for realizing the supramolecular cyclization are obtained. The proposed mechanism is supported by our experimental findings regarding the supramolecular cyclization of polypeptide cylindrical micelles. The cyclization conditions and the revealed mechanism can guide further preparation of uniform toroidal micelles from semiflexible cylindrical micelles in an end-to-end closure manner.

We conceptually design multicompartment gels with supramolecular characteristics by taking advantage of amphiphilic ABC graft copolymers. The ABC graft copolymers contain a solvophilic A backbone and solvophobic B and C grafts, where the C grafts interact with each other via hydrogen bonds. The mechanical properties of supramolecular multicompartment gels under uniaxial tension are studied by coupling dissipative particle dynamics simulations with the nonequilibrium deformation technique. The results show that the supramolecular multicompartment gels exhibit high toughness and recovery properties, while their stiffness is maintained. Due to the physical origin, the superior mechanical properties of supramolecular gels have a tight relation with the structural relaxation of grafts and the association-disassociation dynamics of hydrogen bonds. In addition, the toughness of the multicompartment gels can be further tuned by adjusting the strength and directivity of the hydrogen bonds. The present work unveils the physical origin of the distinct mechanical properties of supramolecular gels, which may provide useful guidance for designing functional gels with superior toughness.

We employed nonequilibrium molecular dynamics simulations to study viscoelastic properties of nanoparticle-tethering polymers. Effects of nanoparticle–polymer interaction and molecular architecture on the viscoelasticity are investigated. The results show that the nanoparticle-tethering polymers with attractive nanoparticle–polymer interaction exhibit enhanced storage and loss moduli relative to the homopolymers or bare nanoparticle/polymer blend. In addition, the storage and loss moduli of nanoparticle-tethering polymers can be further enhanced through tuning their molecular architectures, such as increasing the nanoparticle diameter or decreasing the polymer chain length. From the physical origin, the enhancement of dynamic moduli originates from the slowdown of polymer dynamics, which arises from the attractive nanoparticle–polymer interaction, the tethering covalent bond, and the obstacle of nanoparticles. The present work not only reveals the physical origin of distinct viscoelasticity of nanoparticl...

The hybrid particle–field method is extended to investigate self-assembly and percolating behavior of nanocomposites containing block copolymers and nanoparticles. The self-assembled nanostructures serve as templates to guide organization and distribution of nanoparticles. The percolation threshold of nanoparticles in the host of block copolymers is discussed in terms of composition of block copolymers, radius, and aspect ratio of nanoparticles. The simulated results demonstrate that the block copolymers have a synergistic or antagonistic effect on emergence of percolating network of nanoparticles, depending on the copolymer composition. There exists an optimal value of copolymer composition for lowering the percolation threshold of nanoparticles. In addition, regulating the geometrical shape of nanoparticles further lowers the percolation threshold of nanoparticles dispersed in the block copolymers. These simulated results provide useful guidelines for designing high-performance composite materials with ...

Self-consistent field theory with a dynamic extension is exploited to investigate the kinetics of the lamellar formation of symmetric block copolymers under the direction of external fields. In particular, three types of directed self-assembly methods - a permanent field for chemo-epitaxy, a dynamic field for zone annealing and an integrated permanent/dynamic field - are examined. For the chemo-epitaxy involving sparsely prepatterned substrates or zone annealing, the block copolymers generally develop into polycrystalline nanostructures with multiple orientations due to the lack of strong driving forces for eliminating the long-lived imperfections in a limited time. As the integrated chemo-epitaxy and zone annealing method is applied to the block copolymer systems, single-crystalline nanostructures with precisely registered orientations are achieved in a short annealing time owing to the mutual acceleration of defect annihilations, which cannot be produced by the conventional techniques alone. Furthermore, the integrated method allows the rapid fabrication of well-ordered nanostructures on the extremely sparse prepatterned substrates. Our theoretical work may serve to rationalize the faster modern nanolithographic fabrication of smaller microelectronic components using lower-spatial-frequency templates.

The ability to design and fabricate highly ordered superstructures from nanoscale particles remains a major scientific and technological challenge. Patchy nanoparticles have recently emerged as a novel class of building units to construct functional materials. Using simulations of coarse-grained molecular dynamics, we propose a simple approach to achieve soft nanoparticles with a self-patchiness nature through self-assembly of tethered copolymers with a sequence of inner solvophilic and outer solvophobic blocks. As building units, the patch-like nanoparticles are directed to further assemble into a rich variety of highly ordered superstructures via condensation-coalescence mechanisms. The growth kinetics of the superstructures obeys the kinetic model of the step-growth polymerization process. Our simulations also demonstrate that the intermediate patch-like nanoparticles and the final assembled superstructures can be rationally tuned by changing the number and the composition of the tethered copolymer chains. This strategy of copolymer functionalization conceptually enables the design and fabrication of highly ordered superstructures of nanoparticle ensembles with new horizons for promising applications in soft nanotechnology and biotechnology.

The limited complexity of self-assembled nanostructures of block copolymers seriously impedes their potential utility in the semiconductor industry. Therefore, the customizability of complex nanostructures has been a long-standing goal for the utilization of directed self-assembly in nanolithography. Herein, we integrated an advanced inverse design algorithm with a well-developed theoretical model to deduce inverse solutions of topographical templates to direct the self-assembly of block copolymers into reproducible target structures. The deduced templates were optimized by finely tuning the input parameters of the inverse design algorithm and through symmetric operation as well as nanopost elimination. More importantly, our developed algorithm has the capability to search inverse solutions of topographical templates for aperiodic nanostructures over exceptionally large areas. These results reveal design rules for guiding templates for the device-oriented nanostructures of block copolymers with prospective applications in nanolithography.

We conduct Brownian dynamics simulations to explore the kinetics of living supramolecular polymerization using seeded growth of rod–coil block copolymers as a model system. We model the kinetics of supramolecular polymerization by developing kinetic theory for classical living covalent polymerization with length-dependent rate coefficients. The rate coefficient in the proposed kinetics theory decreases with increasing cylindrical micelle length, which is attributed to micelle rigidity and unique diffusion behavior. Like living covalent polymerization, living supramolecular polymerization can produce low-dispersity assemblies with rigidity via different mechanisms. The results nicely explain the available experimental observations.

Synthetic copolymers of molecular systems serve as an inspiration for creation of one-dimensional copolymer-like superstructures via coassembly of anisometric nanoparticles. In contrast to the covalent and molecular copolymers, the details of formation mechanisms of copolymer-like superstructures, as well as the factors determining their length and the sequences of arranged nanoparticles, are still poorly understood. Herein, we propose a joint theoretical-computational framework to probe into the coassembly mechanism and kinetics of binary mixtures of patchy nanoparticles. By applying the coarse-grained molecular dynamics simulations, it is demonstrated that the coassembly of patchy nanoparticles markedly resembles many aspects of molecular step-growth copolymerization, and the sequences of nanoparticles inside the copolymer-like superstructures can be finely regulated by the relative activity and the initial ingredient of patchy nanoparticles as well as the coassembly strategy. A quantitatively copolymerization-like model is developed to account for the coassembly kinetics of patchy nanoparticles and the sequence distribution of arranged nanoparticles, all governed by the elaborate design of lower-level building units. The jointly theoretical and simulated studies offer mechanistic insights into the copolymerization-like kinetics and the sequence prediction for the coassembly of binary mixtures of patchy nanoparticles, paving the way toward the rational design of copolymer-like superstructures with various sequences and functionalities.

It is a challenging task to realize large-area manufacture of chiral geometries of nanoparticles in solid-state materials, which exhibit strongly chiroptical responses in the visible and near-infrared ranges. Herein, novel nanocomposites, made from mixtures of achiral block copolymers and nanoparticles in a geometrically confined environment, are conceptually proposed to construct the chiral assemblies of nanoparticles through a joint theoretical-calculation framework and experimental discussion. It is found that the nanochannel-confined block copolymers self-assemble into a family of intrinsically chiral architectures, which serve as structural scaffolds to direct the chiral arrangement of nanoparticles. Through calculations of chiral order parameters and simulations of discrete dipole approximation, it is further demonstrated that certain members of this family of nanoparticle assemblies exhibit intense chiroptical activity, which can be tailored by the nanochannel radius and the nanoparticle loading. These findings highlight the multiple levels of structural control over a class of chiral assemblies of nanoparticles and the functionalities of emerging materials via careful design and selection of nanocomposites.

It is an extremely challenging task to construct three-dimensional (3D) well-ordered superstructures with controllable morphologies and predictable internal components. Using computational modeling, we conceive and demonstrate a novel class of templates with topographically and chemically patterned surfaces for directing the self-assembly of symmetric block copolymers. Large-cell simulations of self-consistent field theory corroborate that 3D sophisticated structures of vertical lamellae with different in-plane orientations are achieved and the placements of grain interfaces are regulated by post height and commensurability conditions. Notably, non-orthogonally crossed structures are created by simply modulating the periodicities of post arrays. This work may provide a novel route for experimentalists to fabricate 3D long-range ordered structures with tunable local characteristics.

The self-assembly of colloidal nanoparticles is conceptually analogous to the polymerization of reactive monomers in molecular systems. However, less is known about the polymerization of colloidal nanoparticles into supracolloidal polymers. Herein, using coarse-grained molecular dynamics and theoretical analysis, we reveal the self-assembly mechanism and kinetics of colloidal nanoparticles constructed from triblock terpolymers. The results show that the formation pathway of supracolloidal polymers involves monomer condensation and oligomer coalescence through the manner of end-to-end collisions. In contrast to the polymerization kinetics of molecular systems, the simulations and theoretical analysis definitely demonstrate that the growth of supracolloidal polymers obeys diffusion-controlled step-growth polymerization kinetics with a variable rate coefficient, where the growth rate is dependent upon the concentration of colloidal nanoparticles and the molecular information of triblock terpolymers. Our findings possess wide implications for understanding the growth of supracolloidal polymers, which is important for the rational and precise design of one-dimensional self-assembled superstructures with new horizons for biomedical applications.

We applied a multiscale approach coupling dissipative particle dynamics method with a drift-diffusion model to elucidate the photovoltaic properties of multiblock copolymers consisting of alternating electron donor and acceptor blocks. A series of hierarchical lamellae-in-lamellar structures were obtained from the self-assembly of the multiblock copolymers. A distinct improvement in photovoltaic performance upon the morphology transformation from lamella to lamellae-in-lamella was observed. The hierarchical lamellae-in-lamellar structures significantly enhanced exciton dissociation and charge carrier transport, which consequently contributed to the improved photovoltaic performance. On the basis of our theoretical calculations, the hierarchical nanostructures can achieve much enhanced energy conversion efficiencies, improved by around 25% compared with that of general ones, through structure modulation on the number and size of the small-length-scale domains via the molecular design of multiblock copolymers. Our findings are supported by recent experimental evidence and provide guidance for designing advanced photovoltaic materials with hierarchical structures.