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2018 Volume 36 Issue 6
2018, 36(6):
Abstract:
2018, 36(6): 683-696
doi: 10.1007/s10118-018-2105-z
Abstract:
In nature, many biological soft tissues with synergistic heterostructures, such as sea cucumbers, skeletal muscles and cartilages, exhibit high functionality to adapt to complex environments. In artificial soft materials, hydrogels are similar to biological soft tissues due to the unique integration of "soft and wet" properties and elastic characteristics. However, currently hydrogel materials lack their necessary adaptability, including narrow working temperature windows and uncontrollable mechanics, thus restrict their engineering application in complex environments. Inspired by abovementioned biological soft tissues, researchers have increasingly developed heterostructural gel materials as functional soft materials with high adaptability to various mechanical and environmental conditions. This article summarizes our recent work on high-performance adaptive gel materials with synergistic heterostructures, including the critical design criteria and the state-of-the-art fabrication strategies of our gel materials. The functional adaptation properties of these heterostructural gel materials are also presented in details, including temperature, wettability, mechanical and shape adaption.
In nature, many biological soft tissues with synergistic heterostructures, such as sea cucumbers, skeletal muscles and cartilages, exhibit high functionality to adapt to complex environments. In artificial soft materials, hydrogels are similar to biological soft tissues due to the unique integration of "soft and wet" properties and elastic characteristics. However, currently hydrogel materials lack their necessary adaptability, including narrow working temperature windows and uncontrollable mechanics, thus restrict their engineering application in complex environments. Inspired by abovementioned biological soft tissues, researchers have increasingly developed heterostructural gel materials as functional soft materials with high adaptability to various mechanical and environmental conditions. This article summarizes our recent work on high-performance adaptive gel materials with synergistic heterostructures, including the critical design criteria and the state-of-the-art fabrication strategies of our gel materials. The functional adaptation properties of these heterostructural gel materials are also presented in details, including temperature, wettability, mechanical and shape adaption.
2018, 36(6): 697-702
doi: 10.1007/s10118-018-2056-4
Abstract:
The molecular transfer printing (MTP) technique has been invented to fabricate chemical patterns with high fidelity using homopolymer inks. In this work, we systematically studied the effects of the molecular weights of homopolymer inks and transfer conditions on the MTP process. We explored a large range of molecular weights (~3.5-56 kg·mol-1) of hydroxyl-terminated polystyrene (PS-OH) and hydroxyl-terminated poly(methyl methacrylate) (PMMA-OH) in the MTP process, and found that the resulting chemical patterns on replicas from all five blends were functional and able to direct the assembly of films of the same blends. The transfer temperature and the film annealing sequences had an impact on the MTP process. MTP was sensitive to the transfer temperature and could only be performed within a certain temperature range, i.e. higher than the glass transition temperature (Tg) of copolymers and lower than the rearrangement temperature of the assembled domains. Pre-organization of the blend films was also necessary for MTP since the preferential wetting of PMMA domains at the replica surface might result in the formation of a PMMA wetting layer to prevent the presentation of underlying chemical patterns to the replica surface.
The molecular transfer printing (MTP) technique has been invented to fabricate chemical patterns with high fidelity using homopolymer inks. In this work, we systematically studied the effects of the molecular weights of homopolymer inks and transfer conditions on the MTP process. We explored a large range of molecular weights (~3.5-56 kg·mol-1) of hydroxyl-terminated polystyrene (PS-OH) and hydroxyl-terminated poly(methyl methacrylate) (PMMA-OH) in the MTP process, and found that the resulting chemical patterns on replicas from all five blends were functional and able to direct the assembly of films of the same blends. The transfer temperature and the film annealing sequences had an impact on the MTP process. MTP was sensitive to the transfer temperature and could only be performed within a certain temperature range, i.e. higher than the glass transition temperature (Tg) of copolymers and lower than the rearrangement temperature of the assembled domains. Pre-organization of the blend films was also necessary for MTP since the preferential wetting of PMMA domains at the replica surface might result in the formation of a PMMA wetting layer to prevent the presentation of underlying chemical patterns to the replica surface.
2018, 36(6): 703-711
doi: 10.1007/s10118-018-2067-1
Abstract:
A novel perylene tetracarboxylic acid bisimide (PTCBI) in-chain polyethylene (PE) was first prepared via acyclic diene metathesis (ADMET) polymerization of PTCBI-functionalized α, ω-diene monomer. The polymers could spontaneously self-assemble into hollow cylindrical structures in which the π-π interaction between adjacent PTCBI moieties was enhanced and the electron mobility was possibly promoted. The hydrogenation of as-obtained polymer was readily accomplished, affording the desired precision PTCBI in-chain PE with a saturated backbone, which showed high glass transition temperature (Tg=63℃), relatively wide range of light absorption (λ=200-575 nm), and higher LUMO level (-3.62 eV). It can therefore serve as a superior model for facile construction of functional polyolefin and soluble PTCBI polymer with ordered architecture.
A novel perylene tetracarboxylic acid bisimide (PTCBI) in-chain polyethylene (PE) was first prepared via acyclic diene metathesis (ADMET) polymerization of PTCBI-functionalized α, ω-diene monomer. The polymers could spontaneously self-assemble into hollow cylindrical structures in which the π-π interaction between adjacent PTCBI moieties was enhanced and the electron mobility was possibly promoted. The hydrogenation of as-obtained polymer was readily accomplished, affording the desired precision PTCBI in-chain PE with a saturated backbone, which showed high glass transition temperature (Tg=63℃), relatively wide range of light absorption (λ=200-575 nm), and higher LUMO level (-3.62 eV). It can therefore serve as a superior model for facile construction of functional polyolefin and soluble PTCBI polymer with ordered architecture.
2018, 36(6): 712-719
doi: 10.1007/s10118-018-2079-x
Abstract:
In this study, porous polylactide (PLA) microspheres with different structures were prepared through the multiple emulsion solvent evaporation method. By changing organic solvents (ethyl acetate and chloroform) and adding effervescent salt NH4HCO3 in the inner water phase, microspheres with porous capsular, matrix, microcapsular and multivesicular structures were prepared. The protein encapsulation and release, and the cell growth behavior of porous microspheres were further explored. Under the same inner water phase, microspheres prepared with chloroform had higher protein encapsulation efficiency and less protein release rate as compared with those prepared with ethyl acetate. Cell experiments showed that the relatively rough surface of microspheres prepared with chloroform was more favorable for the cell growth in comparison with the smooth surface of microspheres prepared with ethyl acetate. This study shows a simple and effective method to control the protein release and cell growth behaviors of polymer microspheres by tuning their porous structure.
In this study, porous polylactide (PLA) microspheres with different structures were prepared through the multiple emulsion solvent evaporation method. By changing organic solvents (ethyl acetate and chloroform) and adding effervescent salt NH4HCO3 in the inner water phase, microspheres with porous capsular, matrix, microcapsular and multivesicular structures were prepared. The protein encapsulation and release, and the cell growth behavior of porous microspheres were further explored. Under the same inner water phase, microspheres prepared with chloroform had higher protein encapsulation efficiency and less protein release rate as compared with those prepared with ethyl acetate. Cell experiments showed that the relatively rough surface of microspheres prepared with chloroform was more favorable for the cell growth in comparison with the smooth surface of microspheres prepared with ethyl acetate. This study shows a simple and effective method to control the protein release and cell growth behaviors of polymer microspheres by tuning their porous structure.
2018, 36(6): 720-727
doi: 10.1007/s10118-018-2092-0
Abstract:
2, 5-Furandicarboxylic acid (2, 5-FDCA) has been regarded as the ideal bio-based alternative to terephthalic acid (TPA). In recent years, great efforts have been made to synthesize 2, 5-FDCA through the following methods:(1) oxidation of 5-hydroxymethylfurfural (HMF) in the presence of complex biocatalyst or metallic catalyst; (2) conversion of 2-furoic acid via the well-known Henkel Reaction. Herein, a new strategy for the synthesis of 2, 5-FDCA from furan and acetic anhydride under mild condition is reported. The purity of the resulted 2, 5-FDCA was above 99.9%. Acetic acid and iodoform generated in the reaction were recyclable and no other harmful by-products were detected. The thus-obtained 2, 5-FDCA was applied for the preparation of poly(ethylene furandicarboxylate) (PEF) of high quality in terms of high molecular weight and good appearance.
2, 5-Furandicarboxylic acid (2, 5-FDCA) has been regarded as the ideal bio-based alternative to terephthalic acid (TPA). In recent years, great efforts have been made to synthesize 2, 5-FDCA through the following methods:(1) oxidation of 5-hydroxymethylfurfural (HMF) in the presence of complex biocatalyst or metallic catalyst; (2) conversion of 2-furoic acid via the well-known Henkel Reaction. Herein, a new strategy for the synthesis of 2, 5-FDCA from furan and acetic anhydride under mild condition is reported. The purity of the resulted 2, 5-FDCA was above 99.9%. Acetic acid and iodoform generated in the reaction were recyclable and no other harmful by-products were detected. The thus-obtained 2, 5-FDCA was applied for the preparation of poly(ethylene furandicarboxylate) (PEF) of high quality in terms of high molecular weight and good appearance.
2018, 36(6): 728-735
doi: 10.1007/s10118-018-2066-2
Abstract:
This work offers a typical understanding of the factors that govern the nanostructures of poly(4-vinyl pyridine)-b-polystyrene-b-poly(4-vinyl pyridine) (P4VP-b-PS-b-P4VP) block copolymers (BCs) in dioxane/water, in which water is a selective solvent for the P4VP block. It is achieved through an investigation of the amphiphilic triblock copolymer micelles by variation of three different factors, including water content (above CWC but under the immobile concentration), temperature (ranging from 20℃ to 80℃), and copolymer composition (low and high PS block length). Transition of bead-like micelles to vesicles is observed with the increase of water content due to the increase of interfacial energy between the copolymer and the solvent. Effect of temperature superposed on that of water content results in various morphologies, such as beads, fibers, rods, capsules, toroids, lamellae, and vesicles. The interfacial tension between the BC and the solvent increases with the increase of water content but decreases with the increase of temperature, indicating that the micellar morphologies are resulted from the competitive interplay between the temperature and the water content and always change in a direction that decreases the interfacial energy. Based on the micellar structures obtained in this work and the effects of temperature superposed on water concentration, a diagram of phase evolution of different micellar morphologies is illustrated here, covering the temperature range from 20℃ to 80℃ and the water content changing from 20 vol% to 35 vol%. For the investigation of BC composition, morphological transition of vesicle-to-fiber, for high PS length, is observed as compared with bead-to-capsule for low PS length, as the temperature changes from 20℃ to 80℃. Our research complements the protocols to control over the morphologies and the phase diagram describing P4VP-b-PS-b-P4VP micellar nanostructures in aqueous solution.
This work offers a typical understanding of the factors that govern the nanostructures of poly(4-vinyl pyridine)-b-polystyrene-b-poly(4-vinyl pyridine) (P4VP-b-PS-b-P4VP) block copolymers (BCs) in dioxane/water, in which water is a selective solvent for the P4VP block. It is achieved through an investigation of the amphiphilic triblock copolymer micelles by variation of three different factors, including water content (above CWC but under the immobile concentration), temperature (ranging from 20℃ to 80℃), and copolymer composition (low and high PS block length). Transition of bead-like micelles to vesicles is observed with the increase of water content due to the increase of interfacial energy between the copolymer and the solvent. Effect of temperature superposed on that of water content results in various morphologies, such as beads, fibers, rods, capsules, toroids, lamellae, and vesicles. The interfacial tension between the BC and the solvent increases with the increase of water content but decreases with the increase of temperature, indicating that the micellar morphologies are resulted from the competitive interplay between the temperature and the water content and always change in a direction that decreases the interfacial energy. Based on the micellar structures obtained in this work and the effects of temperature superposed on water concentration, a diagram of phase evolution of different micellar morphologies is illustrated here, covering the temperature range from 20℃ to 80℃ and the water content changing from 20 vol% to 35 vol%. For the investigation of BC composition, morphological transition of vesicle-to-fiber, for high PS length, is observed as compared with bead-to-capsule for low PS length, as the temperature changes from 20℃ to 80℃. Our research complements the protocols to control over the morphologies and the phase diagram describing P4VP-b-PS-b-P4VP micellar nanostructures in aqueous solution.
2018, 36(6): 736-741
doi: 10.1007/s10118-018-2062-6
Abstract:
A new scolopendra-type polymer of polydodecyloxybenzoyl[1, 5]-diazocine (PDBD) was designed and prepared using 2, 5-bis(4-(dodecyloxy)-benzoyl)terephthaloyl azide with trifluoroacetic acid (TFA) via one-pot reaction in good yields. The structure of polymer was characterized using 1H-NMR, 13C-NMR and MALDI-TOF spectra. The polymer PDBD exhibits good thermal stability as measured by TGA and DSC, and can be dissolved well in common organic solvents such as chloroform and tetrahydrofuran. In addition, UV-Vis spectral studies indicate that the polymer PDBD shows unique optical property changes (protonation/deprotonation) in the different trifluoroacetic acid environments. The new polymer is expected to be utilized as an optical functional material for fabricating optical sensors in environmental and biological fields.
A new scolopendra-type polymer of polydodecyloxybenzoyl[1, 5]-diazocine (PDBD) was designed and prepared using 2, 5-bis(4-(dodecyloxy)-benzoyl)terephthaloyl azide with trifluoroacetic acid (TFA) via one-pot reaction in good yields. The structure of polymer was characterized using 1H-NMR, 13C-NMR and MALDI-TOF spectra. The polymer PDBD exhibits good thermal stability as measured by TGA and DSC, and can be dissolved well in common organic solvents such as chloroform and tetrahydrofuran. In addition, UV-Vis spectral studies indicate that the polymer PDBD shows unique optical property changes (protonation/deprotonation) in the different trifluoroacetic acid environments. The new polymer is expected to be utilized as an optical functional material for fabricating optical sensors in environmental and biological fields.
Rheology of Poly(vinyl butyral) Solution Containing Fumed Silica in Correlation with Electrospinning
2018, 36(6): 742-748
doi: 10.1007/s10118-018-2077-z
Abstract:
The rheological properties in question are influenced by many factors, ranging from the characteristics of the given polymer or solvent to the flowing conditions. The primary focus of this study is to analyse the rheological behaviour of poly(vinyl butyral)-Mowital B 60H-(PVB) solutions dissolved in methanol and a blend of these with fumed silica nanoparticles. The preparation of the nanofibrous web and the quality of nanofibres were correlated with the rheology of the polymer solution. It was discerned that drastically intensifying shear viscosity and the elasticity of the solution exerted a negligible effect on the formation of fibres, a finding which has rarely been discussed in the literature. The morphologies and structures of the PVB/silica nanofibrous membranes were investigated by scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy.
The rheological properties in question are influenced by many factors, ranging from the characteristics of the given polymer or solvent to the flowing conditions. The primary focus of this study is to analyse the rheological behaviour of poly(vinyl butyral)-Mowital B 60H-(PVB) solutions dissolved in methanol and a blend of these with fumed silica nanoparticles. The preparation of the nanofibrous web and the quality of nanofibres were correlated with the rheology of the polymer solution. It was discerned that drastically intensifying shear viscosity and the elasticity of the solution exerted a negligible effect on the formation of fibres, a finding which has rarely been discussed in the literature. The morphologies and structures of the PVB/silica nanofibrous membranes were investigated by scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy.
2018, 36(6): 749-755
doi: 10.1007/s10118-018-2059-1
Abstract:
The crystallization behavior of syndiotactic polystyrene (sPS) γ form undergoing annealing at various temperatures was investigated using the thermodynamic phase diagram based on Strobl's crystallization theory. On the basis of the differential scanning calorimetric results, it was observed that γ form melt-recrystallization occurred at a higher temperature with the increasing lamellar thickness, which resulted from the pre-annealing at the elevating temperature after acetone induced crystallization. Further temperature dependent small-angle X-ray scattering (SAXS) measurement revealed the evolution of the γ form lamellae upon heating until phase transition, involving three different regimes:lamellae stable region (25-90℃), melt-recrystallization region (90-185℃) and pre-phase transition region (185-195℃). As a result, recrystallization line, equilibrium recrystallization line and melting line were developed for the sPS γ form crystallization process. Since the melt of γ form involved a γ-to-α/β form phase transition, the melting line was also denoted as the phase transition line in this special case. Therefore, the equilibrium crystallization temperature and melting (phase transition) temperatures were determined at around 390 and 220℃ on the basis of the thermodynamic phase diagram of the sPS γ form.
The crystallization behavior of syndiotactic polystyrene (sPS) γ form undergoing annealing at various temperatures was investigated using the thermodynamic phase diagram based on Strobl's crystallization theory. On the basis of the differential scanning calorimetric results, it was observed that γ form melt-recrystallization occurred at a higher temperature with the increasing lamellar thickness, which resulted from the pre-annealing at the elevating temperature after acetone induced crystallization. Further temperature dependent small-angle X-ray scattering (SAXS) measurement revealed the evolution of the γ form lamellae upon heating until phase transition, involving three different regimes:lamellae stable region (25-90℃), melt-recrystallization region (90-185℃) and pre-phase transition region (185-195℃). As a result, recrystallization line, equilibrium recrystallization line and melting line were developed for the sPS γ form crystallization process. Since the melt of γ form involved a γ-to-α/β form phase transition, the melting line was also denoted as the phase transition line in this special case. Therefore, the equilibrium crystallization temperature and melting (phase transition) temperatures were determined at around 390 and 220℃ on the basis of the thermodynamic phase diagram of the sPS γ form.
2018, 36(6): 756-764
doi: 10.1007/s10118-018-2051-9
Abstract:
In this study, the isothermal crystallization kinetics and crystalline morphology of poly(butylene adipate-co-butylene 1, 4-cyclohexanedicarboxylate) (PBAC), which refers to a copolyester containing a non-planar ring structure, were investigated by differential scanning calorimetry and polarized optical microscopy, and compared with those of neat poly(butylene 1, 4-cyclohexanedicarboxylate) (PBC). The results indicate that the introduction of butylene adipate (BA) unit into PBAC did not change the intrinsical crystallization mechanism. But, the crystallization rate and ability, and equilibrium melting temperature of PBAC copolymers were reduced. All PBC and PBAC copolymers could only form high density of nucleation from melt at given supercooling, while no Maltese cross or ring-banded spherulites could be observed. PBAC copolymers with a high amount of BA unit became amorphous after quenching with liquid nitrogen from melt, while PBC and PBAC copolymers with a low amount of BA unit could still form a large amount of nuclei under the same treatment.
In this study, the isothermal crystallization kinetics and crystalline morphology of poly(butylene adipate-co-butylene 1, 4-cyclohexanedicarboxylate) (PBAC), which refers to a copolyester containing a non-planar ring structure, were investigated by differential scanning calorimetry and polarized optical microscopy, and compared with those of neat poly(butylene 1, 4-cyclohexanedicarboxylate) (PBC). The results indicate that the introduction of butylene adipate (BA) unit into PBAC did not change the intrinsical crystallization mechanism. But, the crystallization rate and ability, and equilibrium melting temperature of PBAC copolymers were reduced. All PBC and PBAC copolymers could only form high density of nucleation from melt at given supercooling, while no Maltese cross or ring-banded spherulites could be observed. PBAC copolymers with a high amount of BA unit became amorphous after quenching with liquid nitrogen from melt, while PBC and PBAC copolymers with a low amount of BA unit could still form a large amount of nuclei under the same treatment.
2018, 36(6): 765-775
doi: 10.1007/s10118-018-2057-3
Abstract:
In the current work, a custom-made vibration injection molding device that can provide oscillatory pressure was utilized to create an injection-molded hierarchical structure. Growth competition among α, β, and γ phases in the injection-molded structure can be studied because of the presence of this hierarchical structure, wherein shish-kebab and spherulite layers were arranged alternately along the thickness direction. The γ crystals only existed in layers subjected to high pressure and shear stress, whereas β crystals formed between the shear layers. The change in trend of the γ fraction was similar to that of parent-to-daughter ratio. In addition, this hierarchical and alternating crystal structure can sharply increase the mechanical properties.
In the current work, a custom-made vibration injection molding device that can provide oscillatory pressure was utilized to create an injection-molded hierarchical structure. Growth competition among α, β, and γ phases in the injection-molded structure can be studied because of the presence of this hierarchical structure, wherein shish-kebab and spherulite layers were arranged alternately along the thickness direction. The γ crystals only existed in layers subjected to high pressure and shear stress, whereas β crystals formed between the shear layers. The change in trend of the γ fraction was similar to that of parent-to-daughter ratio. In addition, this hierarchical and alternating crystal structure can sharply increase the mechanical properties.
2018, 36(6): 776-782
doi: 10.1007/s10118-018-2072-4
Abstract:
A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network (LCN) was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties, respectively. A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN. More importantly, the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation. On the basis of this effective phototuning process, microscopic patterning of photonic film was developed under both fluorescence mode and reflection mode. The work demonstrated here provides a new route to construct photo-responsive photonic film.
A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network (LCN) was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties, respectively. A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN. More importantly, the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation. On the basis of this effective phototuning process, microscopic patterning of photonic film was developed under both fluorescence mode and reflection mode. The work demonstrated here provides a new route to construct photo-responsive photonic film.
2018, 36(6): 783-790
doi: 10.1007/s10118-018-2065-3
Abstract:
Fully biodegradable blends with low shape memory recovery temperature were obtained based on poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC). By virtue of their similar chemical structures, in situ cross-linking reaction initiated by dicumyl peroxide (DCP) between PLA and PPC chains was realized in PLA/PPC blends. Therefore, the compatibility between PLA and PPC was increased, which obviously changed the phase structures and increased the elongation at break of the blends. The compatibilized blends had a recovery performance at 45℃. Combining the changes of phase structures, the mechanism of the shape memory was discussed. It was demonstrated that in situ compatibilization by dicumyl peroxide was effective to obtain eco-friendly PLA/PPC blends with good mechanical and shape memory properties.
Fully biodegradable blends with low shape memory recovery temperature were obtained based on poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC). By virtue of their similar chemical structures, in situ cross-linking reaction initiated by dicumyl peroxide (DCP) between PLA and PPC chains was realized in PLA/PPC blends. Therefore, the compatibility between PLA and PPC was increased, which obviously changed the phase structures and increased the elongation at break of the blends. The compatibilized blends had a recovery performance at 45℃. Combining the changes of phase structures, the mechanism of the shape memory was discussed. It was demonstrated that in situ compatibilization by dicumyl peroxide was effective to obtain eco-friendly PLA/PPC blends with good mechanical and shape memory properties.
2018, 36(6): 791-798
doi: 10.1007/s10118-018-2042-x
Abstract:
Brownian dynamics simulations are employed to explore the effects of chain stiffness and trivalent salt concentration on the conformational behavior of spherical polyelectrolyte brush. The rigid brush adopts bundle-like morphology at a wide range of trivalent salt concentration. The number variation of bundles pinned on the colloid surface shows a non-monotonic profile as a function of the chain stiffness. The radial distributions of monomers and ions and the charge ratio between condensed ions and monomers are calculated. The charge inversion is observed for the high salt concentration regardless of chain rigidity. Furthermore, the pair correlation functions of monomer-monomer and monomer-salt cation are used to elucidate the aggregated mechanism of the bundle-like structure.
Brownian dynamics simulations are employed to explore the effects of chain stiffness and trivalent salt concentration on the conformational behavior of spherical polyelectrolyte brush. The rigid brush adopts bundle-like morphology at a wide range of trivalent salt concentration. The number variation of bundles pinned on the colloid surface shows a non-monotonic profile as a function of the chain stiffness. The radial distributions of monomers and ions and the charge ratio between condensed ions and monomers are calculated. The charge inversion is observed for the high salt concentration regardless of chain rigidity. Furthermore, the pair correlation functions of monomer-monomer and monomer-salt cation are used to elucidate the aggregated mechanism of the bundle-like structure.
