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This work pioneers to combine fast self-assembly of polyhedral oligomeric silsesquioxanes (POSS) nanocage-based giant surfactants with high etching contrast and directed self-assembly for reliable long-range lateral order to create well-aligned sub-10 nm line nanopatterns via reactive ion etching (RIE). Polystyrene-block-oligo(dimethylsiloxane) substituted POSS (PS-b-oDMS 7 POSS) with seven oligo(dimethylsiloxane) at the corners of the POSS nanocage and one polystyrene (PS) tail is designed and synthesized as a giant surfactant with self-assembly behaviors like block copolymer (BCP). In contrast to BCP, oDMS 7 POSS gives a volume-persistent "nanoatom" particle with higher mobility for fast self-assembly and higher segregation strength with PS for smaller feature size. By taking advantage of directed self-assembly using nano-trench fabricated by electron beam lithography, well-ordered nanostructured monolayer with well-aligned parallel oDMS 7 POSS cylinders can be formed by confined self-assembly within the nano-trench. With the optimization of the RIE treatment using O 2 as an etchant, the high etching contrast from the oDMS 7 POSS and PS gives the formation of well-defined line nanopatterns with sub-10 nm critical dimension that can serve as a mask for pattern transfer in lithography. These results demonstrate a cost-effective approach for nanopatterning by utilizing a creatively designed giant surfactant with sub-10 nm feature size and excellent etching contrast for modern lithographic applications., (© 2024 Wiley‐VCH GmbH.)

Biomimicking natural structures to create structural materials with superior mechanical performance is an area of extensive attention, yet achieving both high strength and toughness remains challenging. This study presents a novel bottom-up approach using self-assembled block copolymer templating to synthesize bicontinuous nanohybrids composed of well-ordered nanonetwork hydroxyapatite (HAp) embedded in poly(methyl methacrylate) (PMMA). This structuring transforms intrinsically brittle HAp into a ductile material, while hybridization with PMMA alleviates the strength reduction caused by porosity. The resultant bicontinuous PMMA/HAp nanohybrids, reinforced at the interface, exhibit high strength and toughness due to the combined effects of topology, nanosize, and hybridization. This work suggests a conceptual framework for fabricating flexible thin films with mechanical properties significantly surpassing those of traditional composites and top-down approaches.

This study aims to develop a strategy for the fabrication of multilayer nanopatterns through sequential self-assembly of lamella-forming polystyrene- block -polydimethylsiloxane (PS- b -PDMS) block copolymer (BCP) from solvent annealing. By simply tuning the solvent selectivity, a variety of self-assembled BCP thin-film morphologies, including hexagonal perforated lamellae (HPL), parallel cylinders, and spheres, can be obtained from single-composition PS- b -PDMS. By taking advantage of reactive ion etching (RIE), topographic SiO 2 monoliths with well-ordered arrays of hexagonally packed holes, parallel lines, and hexagonally packed dots can be formed. Subsequently, hole-on-dot and line-on-hole hierarchical textures can be created through a layer-by-layer process with RIE treatment as evidenced experimentally and confirmed theoretically. The results demonstrated the feasibility of creating three-dimensional (3D) nanopatterning from the sequential self-assembly of single-composition PS- b -PDMS via solvent annealing, providing an appealing process for nano-MEMS manufacturing based on BCP lithography.

This work aims to systematically examine the topology effect on the self-assembly of block copolymers. Compositionally, symmetric polystyrene- block -polydimethylsiloxane block copolymers (BCPs) with different chain topologies (diblock, three-arm star-block, and four-arm star-block) and various molecular weights are synthesized. These purposely designed block copolymers are used as a model system to investigate the topology effect on order-to-disorder transition temperature ( T ODT ) by temperature-resolved small-angle X-ray scattering experiments. An increase of the T ODT is observed when the arm number of BCPs with equivalent arm length (i.e., molecular weight) is increased from one to four. Based on the random-phase approximation (RPA), Flory-Huggins interaction parameter (χ) is determined from the regression of the measured T ODT . The observation by differential scanning calorimetry also demonstrates the shifting of the endothermic peak from the order-to-disorder transition of star-blocks to the higher temperature region, consistent with the scattering experiments and the RPA prediction., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

This work aims to examine the effect of self-assembly on the chiroptic responses of the achiral block copolymer (BCP) polystyrene- b -poly(ethylene oxide) (PS- b -PEO) associated with chiral luminophores, ( R )- or ( S )-1,1'-bi-2-naphthol (( R )- or ( S )-BINOL), through hydrogen bonding. With the formation of a well-ordered helical phase (H*), significantly induced circular dichroism (ICD) signals for the PEO block in the mixture can be found. Most interestingly, a remarkable amplification with an extremely large dissymmetry factor of luminescence ( g lum ) from 10 -3 to 0.3 (i.e., induced circular polarized luminescence (iCPL) behavior) for the chiral BINOLs in the mixture can be achieved by the formation of the helical phase (H*) via mesochiral self-assembly. As a result, by taking advantage of BCP for mesochiral self-assembly, it is feasible to create a nanostructured monolith with substantial optical activities, offering promising applications in the design of chiroptic devices.

By taking advantage of the effects of solvent selectivity and topology on high-χ block copolymer (BCP) for self-assembly, network phases with high packing frustration can be formed in self-assembled polystyrene- b -polydimethylsiloxane (PS- b -PDMS). Apart from gyroid with trigonal structure and diamond with tetrahedral structure, a peculiar network phase with space group of [Formula: see text] (Frank-Kasper structure) can be found in six-arm star-block PS- b -PDMS as evidenced by small-angle x-ray scattering. Electron tomography results reveal the network phase with alternating connection of three and four struts. The observed phase behaviors suggest that the network formation is built from the bisectors of dispersive spheres in the Frank-Kasper phase, instead of building connections among them, and thus decipher the origins of complex phase formation due to the adaptive character of malleable mesoatoms.

Background: Depression is a common issue among university students and has been particularly exacerbated during the COVID-19 pandemic. However, limited research has specifically focused on depression among university entrants., Objectives: This study aimed to determine the prevalence of depression severity and identify associated factors during different phases of the COVID-19 pandemic using health screening questionnaires completed by matriculated university students in Singapore., Methods: A repeated cross-sectional study was conducted at a public university in Singapore. Data from health screening questionnaires administered in 2020 and 2021, involving 15,630 newly enrolled university students, were analyzed. The questionnaires covered students' sociodemographic information, physical health status, own and family medical history, lifestyle behaviours, and the Patient Health Questionnaire (PHQ-9). The PHQ-9 was used to measure the severity of depressive symptoms, categorizing into moderate to severe depressive symptoms (MSDS), mild depressive symptoms (MDS), or no depressive symptom (NDS). Multinomial logistic regression was used to assess the sociodemographic, physical and behavioural correlates of depression., Results: The prevalence of MSDS was 1% in both 2020 and 2021, while the rates for MDS were 1.93% in 2020 and 1.64% in 2021. In the 2020 cohort, male freshmen who reported better health had a lower likelihood of experiencing depression. Conversely, students of Malay ethnicity, those majoring in Engineering, those with multiple chronic diseases, monthly alcohol consumers, current smokers, and those with a family history of mental disorder had a higher likelihood of experiencing depression. Moreover, students who lived on-campus in the 2021 cohort were less likely to experience depression than those living off-campus. However, the associations between academic majors, alcohol consumption, and smoking with depression were not significant in the 2021 cohort., Conclusions: This study reported a low prevalence of both MSDS and MDS among university entrants in Singapore. The study further identified three categories of factors associated with depression: sociodemographic, physical, and behavioural. This study suggests policy interventions to enhance targeted social support that address each student group's specific requirements and susceptibilities. A more extensive and comprehensive study is warranted to assess the changes in student mental health status post-COVID-19 pandemic., (© 2024. The Author(s).)

Chirality transfer is essential to acquire helical hierarchical superstructures from the self-assembly of supramolecular materials. By taking advantage of chirality transfers at different length scales through intra-chain and inter-chain chiral interactions, helical phase (H*) can be formed from the self-assembly of chiral block copolymers (BCPs*). In this study, chiral triblock terpolymers, polystyrene-b-poly(ethylene oxide)-b-poly(L-lactide) (PS-PEO-PLLA), and polystyrene-b-poly(4-vinylpyridine)-b-poly(L-lactide) (PS-P4VP-PLLA) are synthesized for self-assembly. For PS-PEO-PLLA with an achiral PEO mid-block that is compatible with PLLA (chiral end-block), H* can be formed while the block length is below a critical value. By contrast, for the one with achiral P4VP mid-block that is incompatible with PLLA, the formation of H* phase would be suppressed regardless of the length of the mid-block, giving cylinder phase. Those results elucidate a new type of chirality transfer across the phase domain that is referred as cross-domain chirality transfer, providing complementary understanding of the chirality transfer at the interface of phase-separated domains., (© 2023 Wiley-VCH GmbH.)

Inspired by knobby starfish, this work demonstrates a bottom-up approach for fabricating a calcite single-crystal (CSC) with a diamond structure by exploiting the self-assembly of the block copolymer and corresponding templated synthesis. Similar to the knobby starfish, the diamond structure of the CSC gives rise to a brittle-to-ductile transition. Most interestingly, the diamond-structured CSC fabricated exhibits exceptional specific energy absorption and strength with lightweight character superior to natural materials and artificial counterparts from a top-down approach due to the nanosized effect. This approach provides the feasibility for creating mechanical metamaterials with the combined effects of the topology and nanosize on the mechanical performance.

The global population has been severely affected by the coronavirus disease 2019 (COVID-19) pandemic, however, with older age identified as a risk factor, children have been underprioritized. This article discusses the factors contributing to the less severe response observed in children following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including, differing viral entry receptor expression and immune responses. It also discusses how emerging and future variants could present a higher risk to children, including those with underlying comorbidities, in developing severe disease. Furthermore, this perspective discusses the differential inflammatory markers between critical and non-critical cases, as well as discussing the types of variants that may be more pathogenic to children. Importantly, this article highlights where more research is urgently required, in order to protect the most vulnerable of our children., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ho, Bowen, Blyth, Imrie, Kollmann, Stick and Kicic.)

Herein, this work aims to directly visualize the morphological evolution of the controlled self-assembly of star-block polystyrene- block -polydimethylsiloxane (PS- b -PDMS) thin films via in situ transmission electron microscopy (TEM) observations. With an environmental chip, possessing a built-in metal wire-based microheater fabricated by the microelectromechanical system (MEMS) technique, in situ TEM observations can be conducted under low-dose conditions to investigate the development of film-spanning perpendicular cylinders in the block copolymer (BCP) thin films via a self-alignment process. Owing to the free-standing condition, a symmetric condition of the BCP thin films can be formed for thermal annealing under vacuum with neutral air surface, whereas an asymmetric condition can be formed by an air plasma treatment on one side of the thin film that creates an end-capped neutral layer. A systematic comparison of the time-resolved self-alignment process in the symmetric and asymmetric conditions can be carried out, giving comprehensive insights for the self-alignment process via the nucleation and growth mechanism.

Many sophisticated chiral materials are found in living organisms, giving specific functions and required complexity. Owing to the remarkable optical properties of chiral materials, they have drawn significant attention for the development of synthetic materials to give optical activities for appealing applications. In contrast to a top-down approach, the bottom-up approach from self-assembled systems with chiral host-achiral guest and achiral guest-chiral host for induced circular dichroism and induced circularly polarized luminescence has greatly emerged because of its cost-effective advantage with easy fabrication for mesoscale assembly. Self-assembled hierarchical textures with chiral sense indeed give significant amplification of the dissymmetry factors of absorption and luminescence (g abs and g lum ), resulting from the formation of well-ordered superstructures and phases with the building of chromophores and luminophores. By taking advantage of the microphase separation of block copolymers via self-assembly, a variety of well-defined chiral nanostructures can be formed as tertiary superstructures that can be further extended to quaternary phases in bulk or thin film. In this article, a conceptual perspective is presented to utilize the self-assembly of chiral block copolymers with chiral communications, giving quaternary phases with well-ordered textures at the nanoscale for significant enhancement of dissymmetry factors., (© 2022 Wiley-VCH GmbH.)

Herein, this work aims to carry out controlled self-assembly of single-composition block copolymer for the fabrication of various nanonetwork silica monoliths. With the use of lamellae-forming polystyrene- block -polydimethylsiloxane (PS- b -PDMS), nanonetwork-structured films could be fabricated by solvent annealing using a PS-selective solvent (chloroform). By simply tuning the flow rate of nitrogen purge to the PS-selective solvent for the controlled self-assembly of the PS- b -PDMS, gyroid- and diamond-structured monoliths can be formed due to the difference in the effective volume of PS in the PS- b -PDMS during solvent annealing. As a result, well-ordered nanonetwork SiO 2 (silica) monoliths can be fabricated by templated sol-gel reaction using hydrofluoric acid etched PS- b -PDMS film as a template followed by the removal of the PS. This bottom-up approach for the fabrication of nanonetwork materials through templated synthesis is appealing to create nanonetwork materials for various applications.

Inspired by Mantis shrimp, this work aims to suggest a bottom-up approach for the fabrication of nanonetwork hydroxyapatite (HAp) thin film using self-assembled polystyrene- block -polydimethylsiloxane (PS- b -PDMS) block copolymer (BCP) with a diamond nanostructure as a template for templated sol-gel reaction. By introducing poly(vinylpyrrolidone) (PVP) into precursors of calcium nitrate tetrahydrate and triethyl phosphite, which limits the growth of forming HAp nanoparticles, well-ordered nanonetwork HAp thin film can be fabricated. Based on nanoindentation results, the well-ordered nanonetwork HAp shows high energy dissipation compared to the intrinsic HAp. Moreover, the uniaxial microcompression test for the nanonetwork HAp shows high energy absorption per volume and high compression strength, outperforming many cellular materials due to the topologic effect of the well-ordered network at the nanoscale. This work highlights the potential of exploiting BCP templated synthesis to fabricate ionic solid materials with a well-ordered nanonetwork monolith, giving rise to the brittle-to-ductile transition, and thus appealing mechanical properties with the character of mechanical metamaterials.

This paper presents a facile method for fabricating a thin-film sample with a high asymmetry value of induced circularly polarized luminescence (iCPL) (|g lum | = 2.0 × 10 -3 ). The method involves mixing stereoregular poly(methyl methacrylate) (PMMA) and chiral chromophore (2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE)) to form a complex with a dynamic helical conformation of poly(methyl methacrylate) (PMMA) associated with TFAE via hydrogen bonding. This dynamic helical conformation can be stabilized by the stereocomplexation of a pair of stereoregular PMMA, where the TFAE is sandwiched between a double-helix isotactic PMMA and single-helix syndiotactic PMMA, resulting in a preferential one-handed helical conformation with a high value of iCPL from self-assembly.

This work aims to demonstrate a facile method for the controlled orientation of nanostructures of block copolymer (BCP) thin films. A simple diblock copolymer system, polystyrene- block -polydimethylsiloxane (PS- b -PDMS), is chosen to demonstrate vacuum-driven orientation for solving the notorious low-surface-energy problem of silicon-based BCP nanopatterning. By taking advantage of the pressure dependence of the surface tension of polymeric materials, a neutral air surface for the PS- b -PDMS thin film can be formed under a high vacuum degree (∼10 -4 Pa), allowing the formation of the film-spanning perpendicular cylinders and lamellae upon thermal annealing. In contrast to perpendicular lamellae, a long-range lateral order for forming perpendicular cylinders can be efficiently achieved through the self-alignment mechanism for induced ordering from the top and bottom of the free-standing thin film.

Through the morphological evolution to give highly optimized complex architectures at different length scales, fine-tuned textures for specific functions in living organisms can be achieved in nature such as a bone core with very complicated porous architecture to attain a significant structural efficiency attributed to delicately structured ligaments and density gradients. As inspired by nature, materials with periodic network structures (i.e., well-defined porous textures) in the nanoscale are appealing and promising for innovative properties. Biomimicking from nature, organic and/or inorganic nanonetworks can be synthetically fabricated, giving broadness and effectiveness when tuning the desired properties. Metamaterials are materials whose effective properties do not result from the bulk behavior of the constituent materials but rather mainly from their deliberate structuring. The performances of fabricating metamaterials will depend on the control of size, shape, order, and orientation of the forming textures. One of the appealing textures for the deliberate structuring is network architecture. Network materials possess self-supporting frameworks, open-cell character, high porosity, and large specific surface area, giving specific functions and complexity for diverse applications. As demonstrated by recent studies, exceptional mechanical performances such as negative thermal expansion, negative Poisson's ratio, and twisting under uniaxial forces can be achieved by the effect of the deliberate structuring with nanonetwork textures. In contrast to a top-down approach, a bottom-up approach is cost-effective, and also it can overcome the size limitation to reach nanoscale fabrication. It can be foreseen that network metamaterials with a feature size of tens of nanometers (referred as nanonetwork metamaterials) may provide new comprehension of the structure and property relationships for various materials. The self-assembly of block copolymers (BCPs) is one of the most used methods to build up well-ordered nanostructured phases from a bottom-up approach with precise control of size, shape, and orientation in the thin films for realistic applications. In this account, we summarize recent advancements in the fabrication of nanohybrids and nanoporous materials with well-ordered nanonetwork textures even with controlled helicity by combining block copolymer self-assembly and templated syntheses for mechanical and optical applications with superior properties beyond nature as metamaterials as well as chiral metamaterials with new properties for chiroptic applications such as chiral plasmonics, beam splitter, and negative refraction. The description of the fundamental facets of a nonconventional structure-property relationship with the characters of metamaterials and the state-of-the-art methodologies to fabricate nanonetworks using block copolymer self-assembly will stimulate research activities for the development of nanonetwork metamaterials with exceptional individual and multifunctional properties for futuristic devices.

Significant enhancement of segment-scale chirality, as measured by vibrational circular dichroism (VCD), is observed in the helical phase (H*) of polylactide-based chiral block copolymers (BCPs*) due to the mesoscale chirality of the microphase-separated domains. Here, we report a weaker, yet meaningful, enhancement on the VCD signal of a double gyroid phase (DG) as compared to a double diamond phase (DD) and disordered phase from the same diblock BCPs*. Residual VCD enhancement indicates a weak degree of chiral symmetry breaking, implying the formation of a chiral double gyroid (DG*) instead of the canonical achiral form. Calculations on the basis of orientational self-consistent field theory, comparing coupling between the segmental-scale preference of an intradomain twist and morphological chirality, show that a transition between DG and DG* takes place above the critical chiral strength, driving a weak volume asymmetry between the two enantiomeric single networks of DG*. The formation of nanostructures with controllable mesoscale chiral asymmetry indicates a pathway for the amplification of optical activity driven by self-assembly.

Herein, this work aims to fabricate well-ordered nanonetwork epoxy resin modified with poly(butyl acrylate)- b -poly(methyl methacrylate) (PBA- b -PMMA) block copolymer (BCP) for enhanced energy dissipation using a self-assembled diblock copolymer of polystyrene- b -poly(dimethylsiloxane) (PS- b -PDMS) with gyroid and diamond structures as templates. A systematic study of mechanical properties using nanoindentation of epoxy resin with gyroid- and diamond-structures after modification revealed significant enhancement in energy dissipation, with the values of 0.36 ± 0.02 nJ (gyroid) and 0.43 ± 0.03 nJ (diamond), respectively, when compared to intrinsic epoxy resin (approximately 0.02 ± 0.002 nJ) with brittle characteristics. This enhanced property is attributed to the synergic effect of the deliberate structure with well-ordered nanonetwork texture and the toughening of BCP-based modifiers at the molecular level. In addition to the deliberate structural effect from the nanonetwork texture, the BCP modifier composed of epoxy-philic hard segment and epoxy-phobic soft segment led to dispersed soft-segment domains in the nanonetwork-structured epoxy matrix with superior interfacial strength for the enhancement of applied energy dissipation.

Background: Narrative e-Writing Intervention (NeW-I) is a novel psycho-socio-spiritual intervention which aims to bridge gaps in paediatric palliative care by providing anticipatory grief support to parent-caregivers who are looking after their child with a chronic life-threatening illness in Singapore. This is done via a therapist-facilitated smartphone app that focuses on strengths and meaning derived from parents' caregiving journey. NeW-I is empirically informed by an international systematic review and a Singapore-based qualitative inquiry on the lived experience of parental bereavement and supported by anticipatory grief interventions literature for improving the holistic well-being for parent-caregivers of seriously ill children. NeW-I is implemented in Singapore as an open-label two-armed randomized controlled trial comprising an intervention and control group., Methods: This study examined the acceptability (via analysis of participants' post-intervention qualitative feedback and responses to a post-intervention evaluation survey) and feasibility (via records and memos of therapists' experience of delivering the intervention) of NeW-I among 26 intervention participants drawn from the larger trial., Results: Framework analysis of participants' post-intervention feedback revealed four themes, namely: (i) Meaningful opportunity for reflection, (ii) Congruity with parent-caregivers' needs, (iii) Compatibility of online narrative writing and (iv) Sustainability and enhancement recommendations. The post-intervention evaluation survey showed that participants were overall satisfied with their NeW-I experience with a large number of participants acknowledging that NeW-I had improved their spiritual well-being, hopefulness about the future and perception of social support that was available to them, as well as lessened their feelings of sadness and depression, caregiver burden and fear and anxiety about their child's illness. The research team found it feasible to deliver the intervention in the current setting., Conclusion: NeW-I is an innovative e-health tool that could immeasurably value-add to paediatric palliative care services for Asian families in Singapore and around the world., Trial Registration: ClinicalTrials.gov, ID: NCT03684382 , Verified: September 2018., (© 2022. The Author(s).)

Herein, vibrational circular dichroism (VCD) measurements were carried out to study the kinetics of cold-crystallized poly(D-lactide) (PDLA) at the molecular level via qualitative analysis. The amplification of the VCD signals from intra- and inter-chain chiral interactions suggests the formation of partially ordered PDLA, followed by heterogeneous nucleation for crystallization. These results were further supported by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and Fourier transform infrared (FTIR) spectroscopy analyses.