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Manipulation and Deposition of Complex, Functional Block Copolymer Nanostructures using Optical Tweezers
摘要： Block copolymer self-assembly has enabled the creation of a range of solution-phase nanostructures with applications from optoelectronics and biomedicine to catalysis. However, to incorporate such materials into devices a method that facilitates their precise manipulation and deposition is desirable. Herein we describe how optical tweezers can be used to trap, manipulate, and pattern individual cylindrical micelles and larger hybrid micellar materials. Through the combination of TIRF imaging and optical trapping we can precisely control the three-dimensional motion of individual cylindrical block copolymer micelles in solution, enabling the creation of customizable arrays. We also demonstrate that dynamic holographic assembly enables the creation of ordered customizable arrays of complex hybrid block copolymer structures. By creating a program which automatically identifies, traps and then deposits multiple assemblies simultaneously we have been able to dramatically speed up this normally slow process, enabling the fabrication of arrays of hybrid structures containing hundreds of assemblies in minutes rather than hours.
关键词： optical trapping,directed assembly,block copolymers,self-assembly,nanofibers
更新于2025-11-21 11:24:58
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Crosslink network and phenyl content on the optical, hardness, and thermal aging of PDMS LED encapsulant
摘要： This work aims to synthesize new series of polysiloxane copolymer through hydrosilylation reaction based on different level of crosslink densities and phenyl content. The results revealed that polysiloxanes resins with phenyl rings increased viscosity up to 3800 cps while displaying a relatively high refractive index of 1.531. The asymmetric phenyl substitution onto chain backbone led to formation of densely packed structure resulting in reduced water absorption and gas permeability of PDMS resins. High level of crosslinking contributed to a high shore A hardness and adhesion strength. It displayed transparency of 97% whose percentage reduction was 1.6% under thermal and 0.6% UV aging. No obvious discoloration was observed during accelerated thermal aging up to 210 min at 80 (cid:1)C. These results are key attributes that make the synthesized polysiloxane series as ideal candidate for high brightness LED encapsulant. ? 2019 Wiley Periodicals, Inc. ? 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47895.
关键词： copolymers,thermal properties,ring-opening polymerization,optical properties,synthesis and processing techniques
更新于2025-11-19 16:56:42
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Low-dielectric-constant aromatic homopolyimide and copolyimide derived from pyromellitic dianhydride, 4,4′-oxydianiline, 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene
摘要： Low-dielectric-constant aromatics, homopolyimide and copolyimide, were introduced. Homopolyimides were prepared by pyromellitic dianhydride (PMDA) as an anhydride monomer and 4,40-oxydianiline (ODA), 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as an amine monomer. The copolyimides were prepared with PMDA as an anhydride monomer, ODA as an amine monomer with the addition of 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as another amine monomer. The polyimides were well characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, thermomechanical analysis, dielectric measurements, and tensile testing. The homopolyimide and copolyimides showed lower dielectric constants than the homopolyimide formed by ODA and PMDA. The results also indicate that the interchain distance, the quantities of phenyl ether, and the position of the substitute are factors that not only affected the thermal performance of polyimide by improving the molecular ?exibility but also reduced the dielectric constant of polyimide by increasing the free volume of the molecular chain and decreasing the polarization points per unit volume.
关键词： dielectric properties,copolymers,polyimides,films
更新于2025-09-23 15:23:52
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Organic Transistor Based on Cyclopentadithiophene-Benzothiadiazole Donor-Acceptor Copolymer for the Detection and Discrimination between Multiple Structural Isomers
摘要： Distinguishing structural isomers is a critical and challenging task for biotechnology, chemical industry, and environmental monitoring. Approaches currently available are limited in terms of selectivity and simplicity. In this paper, a highly sensitive organic field-effect transistor (OFET) using the cyclopentadithiophene-benzothiadiazole (CDT-BTZ) copolymers as a semiconductor is presented for easy and selective detection of different families of structural isomers, as well as between different isomers within each family. High accuracy discrimination is achieved over a range of concentrations using only a single sensing parameter derived from the OFET characteristic transfer curve. As a reference, other homopolymer- and donor–acceptor copolymer-based OFET sensors are examined but do not have an equivalent sensing performance to that of the CDT-BTZ-based OFETs. Investigating the link between isomer absorption and swelling, supramolecular order and energy levels of the active layer reveals a unique effect of each isomer on the energy bands of the semiconducting polymer.
关键词： isomers,donor–acceptor copolymers,gas sensor,organic field-effect transistor,xylenes
更新于2025-09-23 15:23:52
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Single-Crystal Poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b′]dithiophen-2-yl)- <i>alt</i> -[1,2,5]thiadiazolo[3,4- <i>c</i> ]pyridine] Nanowires with Ultrahigh Mobility
摘要： We fabricated single-crystal poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']-dithiophen-2-yl)-alt-[1,2,5]thiadiazolo-[3,4-c]pyridine] (PCDTPT) nanowires with ultrahigh mobility using a liquid-bridge-mediated nanotransfer molding method. The structural analysis of the single-crystal PCDTPT nanowires reveals that PCDTPT crystals have a triclinic structure, and the nanowires grow parallel to PCDTPT backbone chains, which provide important insights into its intrinsic charge transport. The single-crystal PCDTPT nanowire exhibits a superior charge carrier mobility of 72.94 ± 18.02 cm2 V-1 s-1 (maximum mobility up to 92.64 cm2 V-1 s-1), which is a record high value among conjugated polymers till date. In the single-crystal PCDTPT nanowire, the backbone chains in the linear structure along the nanowire growth axis lead to strong backbone delocalization, resulting in highly conductive polymer backbones and a drastic increase in charge carrier mobility. In addition, the single-crystal PCDTPT nanowire shows good environmental stability under air conditions compared to small-molecule organic semiconductors.
关键词： donor-acceptor-conjugated copolymers,liquid-bridge-mediated nanotransfer molding,PCDTPT,single-crystal polymer nanowire
更新于2025-09-23 15:23:52
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Bio-Inspired Structural Colors based on Linear Ultra-High Molecular Weight Block Copolymers
摘要： Ultra-high molecular weight (UHMW) block copolymers (BCPs) are promising candidates for the fabrication of photonic materials. Here, we demonstrate the synthesis and self-assembly capability of well-defined amphiphilic UHMW BCPs with overall molar masses up to 4432 kg mol-1 obtained via living anionic polymerization. BCP micelles featuring hydrodynamic diameters in the range of the wavelength of the visible light to the near infrared region (300-1143 nm) are used for colloidal crystal formation. By varying the BCP composition brilliant structural colours can be observed. Microphase separation of the UHMW BCPs in the bulk state reveals uniform domains and showing blue to green structural color transitions. Finally, we provide examples of how BCP structural control can be used to generate reversibly switchable solvatochromatic optical sensors.
关键词： morphology,block copolymers,structural colors,self-assembly,anionic polymerization,micellar photonic crystals,photonic materials
更新于2025-09-23 15:23:52
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Hierarchical Photonic Pigments <i>via</i> the Confined Self-Assembly of Bottlebrush Block Copolymers
摘要： Hierarchical, structurally colored materials offer a wide variety of visual effects that cannot be achieved with standard pigments or dyes. However, their fabrication requires simultaneous control over multiple length-scales. Here we introduce a robust strategy for the fabrication of hierarchical photonic pigments via the confined self-assembly of bottlebrush block copolymers within emulsified microdroplets. The bottlebrush block copolymer self-assembles into highly ordered concentric lamellae, giving rise to a near perfect photonic multi-layer in the solid-state, with reflectivity up to 100%. The reflected color can be readily tuned across the whole visible spectrum by either altering the molecular weight or by blending the bottlebrush block copolymers. Furthermore, the developed photonic pigments are responsive, with a selective and reversible color change observed upon swelling in different solvents. Our system is particularly suited for the scalable production of photonic pigments, arising from their rapid self-assembly mechanism and size-independent color.
关键词： photonic crystals,confined self-assembly,microspheres,structural colors,bottlebrush block copolymers
更新于2025-09-23 15:23:52
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Synthesis of new zinc (II) phthalocyanine conjugates with block copolymers for cancer therapy
摘要： Synthetic routes towards new conjugates of hydrophilic zinc(II) phthalocyanine (ZnPc) with poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic P123) and poly(L-lactide) (PLLA), are described. The main semiproduct ZnPc was obtained by heating 4-nitrophthalimide with urea and zinc chloride, followed by the reduction step. Steglich esterification was used to synthesize two ZnPc-conjugated block copolymers, further utilized in fabrication of polymeric micelles (PMs) - functionalized with the zinc(II) phthalocyanine-type moiety. Biological evaluation of the PMs indicated an acceptable biocompatibility level in accord with requirements in the field of nanotheranostics and nanomedicine.
关键词： fluorescent polymeric micelles,cyclotetramerization,Steglich esterification,in vitro biological evaluation,ZnPc-conjugated block copolymers,diagnostic marker
更新于2025-09-23 15:22:29
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Ordered Mesoporous TiO <sub/>2</sub> Gyroids: Effects of Pore Architecture and Nb-Doping on Photocatalytic Hydrogen Evolution under UV and Visible Irradiation
摘要： Pure and Nb-doped TiO2 photocatalysts with highly ordered alternating gyroid architecture and well-controllable mesopore size of 15 nm via co-assembly of a poly(isoprene)-block-poly(styrene)-block-poly(ethylene oxide) block copolymer are synthesized. A combined effort by electron microscopy, X-ray scattering, photoluminescence, X-ray photoelectron spectroscopy, Raman spectroscopy, and density functional theory simulations reveals that the addition of small amounts of Nb results in the substitution of Ti4+ with isolated Nb5+ species that introduces inter-bandgap states, while at high concentrations, Nb prefers to cluster forming shallow trap states within the conduction band minimum of TiO2. The gyroidal photocatalysts are remarkably active toward hydrogen evolution under UV and visible light due to the open 3D network, where large mesopores ensure efficient pore diffusion and high photon harvesting. The gyroids yield unprecedented high evolution rates beyond 1000 μmol h?1 (per 10 mg catalyst), outperforming even the benchmark P25-TiO2 more than fivefold. Under UV light, the Nb-doping reduces the activity due to the introduction of charge recombination centers, while the activity in the visible triple upon incorporation is owed to a more efficient absorption due to inter-bandgap states. This unique pore architecture may further offer hitherto undiscovered optical benefits to photocatalysis, related to chiral and metamaterial-like behavior, which will stimulate further studies focusing on novel light–matter interactions.
关键词： photocatalysis,block copolymers,titanium dioxide,self-assembly
更新于2025-09-23 15:21:01
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Controlled synthesis of gold nanoparticles in copolymers nano-molds by x-ray radiolysis
摘要： We show by x-ray and neutron small angle scattering that gold nanoparticles with controlled sizes and morphologies can be obtained by the metallic reduction of AuCl4- ions trapped in 3D organic molds by x-ray radiolysis. The molds are spherical frozen micelles of polystyrene‐b‐poly(dimethylaminoethyl methacrylate) (PS‐b‐PDMAEMA) block copolymer in acidic aqueous solution with a PS spherical core surrounded by a corona of PDMAEMA chains in good solvent. The behavior of micelles is controlled by the [AuCl4-]/[DMAEMA] ratio RAuCl4-/DMAEMA. At low gold concentration, AuCl4- ions condense on the positively charged DMAEMA moieties without changing the behavior of the PDMAEMA chains. At intermediate gold concentration, the ions induce a progressive contraction of the corona’s chains and dehydration of micelles. At large gold concentration, the corona becomes a fully dry phase loaded with gold ions, which induces micelle aggregation. The radiolysis of the solution by an intense x-ray beam produces different types of gold nanoparticles with respect to RAuCl4-/DMAEMA and irradiation time. At RAuCl4-/DMAEMA = 0.033, the irradiation produces in a first step gold clusters in the micelle corona which in a second step merge to form nanoparticles of a similar size to the one of the micelle. Conversely, at RAuCl4-/DMAEMA = 0.33, micelles do not operate as templates but only as nucleation zones and large nanoparticles grow outside the micelles.
关键词： gold nanoparticles,copolymers template,x-ray radiolysis,small angle scattering,synthesis
更新于2025-09-23 15:21:01