Polystyrene Core Research Articles

Experimental evaluation of structural insulated panels outfitted with phase change materials

Structural insulated panels (SIPs) outfitted with phase change materials (PCMs) are high thermal performance envelope components because they combine the high insulation properties of SIPs with the thermal storage properties of PCMs. The integrated system is known as PCMSIP (Medina et al., 2008). The main objective of this research was to develop an optimal PCMSIP based on SIP core materials, PCM encapsulating materials, and configurations (horizontal vs. vertical) of the encapsulating elements. A dynamic wall simulator was used for the experimental testing. The results showed that heat fluxes through the SIPs were reduced when the SIPs were made using urethane core as opposed to expanded polystyrene (EPS) core. In general, SIPs outfitted with PCM showed lower peak heat fluxes when compared to identical SIPs but without PCM. PVC as an encapsulating material was the least effective material for this purpose and the configuration of the encapsulating elements mattered. The horizontal configuration showed to be more effective in reducing peak heat fluxes through the SIPs.

Spherical Polyelectrolyte Brushes as Templates to Prepare Hollow Silica Spheres Encapsulating Metal Nanoparticles.

Integrating hollow silica spheres with metal nanoparticles to fabricate multifunctional hybrid materials has attracted increasing attention in catalysis, detection, and drug delivery. Here, we report a simple and general method to prepare hollow silica spheres encapsulating silver nanoparticles (Ag@SiO2) based on spherical polyelectrolyte brushes (SPB), which consist of a polystyrene core and densely grafted poly (acrylic acid) (PAA) chains. SPB were firstly used as nanoreactors to generate silver nanoparticles in situ and then used as sacrificial templates to prepare hybrid hollow silica spheres. The resulted Ag@SiO2 composites exhibit high catalytic activity and good reusability for the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. More importantly, this developed approach can be extended to the encapsulation of other metal nanoparticles such as gold nanoparticles into the hollow silica spheres. This work demonstrates that SPB are promising candidates for the preparation of hollow spheres with encapsulated metal nanoparticles and the resulted hybrid spheres show great potential applications in catalysis.

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties.

We report on the synthesis of composite nanobeads with antibacterial properties. The particles consist of polystyrene cores that are surrounded by sulfonic gel shells with embedded silver nanoparticles. The nanocomposite beads are prepared by sulfonation of polystyrene particles followed by accumulation of silver ions in the shell layer and subsequent reduction with sodium borohydride. The resulting material has been characterized by electron microscopy, vibrational and X-ray photoelectron spectroscopy and several other experimental techniques. It was shown that sodium borohydride reduces silver ions embedded in the gel layer producing silver nanoparticles but also transforms a fraction of sulfonic groups in the polymer to moieties with sulfur in a lower oxidation state, likely thiols. It is hypothesized that the generated thiol groups are anchoring the nanoparticles in the gel shell of the nanobeads stabilizing the whole structure. The silver-decorated nanobeads appear to be a promising material with considerable antimicrobial activity and were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. The determined minimum inhibitory (MIC) and minimum biofilm inhibitory (MBIC) concentrations are comparable to those of non-incorporated silver nanoparticles.

Interaction among Spherical Polyelectrolyte Brushes in Concentrated Aqueous Solution

Interaction among concentrated spherical polyelectrolyte brushes (SPB) dispersions in water was systematically investigated by means of small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and rheological methods. SPB consist of a core of polystyrene (PS) and a poly(acrylic acid) (PAA) brush shell. The "polyelectrolyte peak" appeared in SAXS spectra and was observed in WAXS curves for the first time. The size of the polyelectrolyte peak and the rheological properties of SPB were found to be strongly effected by SPB concentration, pH, and ionic strength. Combined with SAXS, WAXS, and rheological results, it is confirmed that the polyelectrolyte peak is originated from local ordered structures of polyelectrolyte chains bridged by counterions in the overlapping area among SPB driven by electrostatic interactions.

Preparation of hollow silica nanoparticles using cationic spherical polyelectrolyte brushes as catalytic template

This paper presents a facile procedure to fabricate uniform-sized hollow silica nanoparticles (SNP) under a mild condition by using cationic spherical polyelectrolyte brushes (SPB) with a polystyrene (PS) core and densely grafted poly(2-aminoethyl methacrylate hydrochloride) (PAEMH) brush shell as a catalytic template. By changing the brush layer thickness of SPB, hollow SNP with different silica shell thickness could be easily obtained. This method provides a new way for the preparation of hollow SNP without additional catalyst. The obtained hollow SNP exhibited a high-drug encapsulation efficiency (80%) for doxorubicin hydrochloride (DOX), should be of significance in the fields of drug delivery, cancer therapy, and bioimaging.

Core-Cross-Linked Micelles Made by RAFT Polymerization with a Polycationic Outer Shell Based on Poly(1-methyl-4-vinylpyridinium)

A convergent synthesis of amphiphilic polymers with a polystyrene (PS) core and a polyelectrolytic poly(1-methyl-4-vinylpyridinium iodide) (P4VPMe+I–) shell is reported. The polymers were obtained by reversible addition–fragmentation chain transfer (RAFT) polymerization in water using a trithiocarbonate chain transfer agent [R0-SC(S)SPr, R0 = −C(Me)(CN)CH2CH2COOH]. Two types of particle structure, both having a spherical morphology and diameters in the 85–150 nm range, have been obtained as stable latexes with polymer content up to 10% in weight. The first structure consists of core-cross-linked micelles (CCMs), where amphiphilic P4VPMe+I–-b-PS arms are cross-linked at the hydrophobic end by the use of diethylene glycol dimethacrylate. The Coulombic repulsion between the outer shells of the precursor micelles ensures the absence of macrogelation during the cross-linking step. The second structure consists of nanogels (NGs), where the entire hydrophobic core is cross-linked during the last step of simultaneous chain extension and cross-linking of a P4VPMe+I–-b-PS intermediate with a short PS block. The lack of radical polymerization for the 4VPMe+I– monomer and the lack of chain extension with styrene for a R0-P4VPMe+I–-SC(S)SPr intermediate were circumvented by the synthesis of R0-P4VP-b-PS-SC(S)SPr containing a short PS block by sequential RAFT polymerization of 4-vinylpyridine (4VP) and styrene, followed by quantitative cationization of the P4VP block by MeI and subsequent sequential (for the CCMs) or simultaneous (for the NGs) chain extension and cross-linking.

Synthesis of magnetite loaded fluorescence micelles of triblock copolymer

Abstract Magnetic micelles with fluorescence dyes were fabricated by self-assembly of triblock copolymer followed by in situ templated coprecipitation method. Nile red was encapsulated into the polystyrene core of the triblock copolymer confirmed by fluorescence measurement. The magnetic nanoparticles are selectively chemisorbed on the poly(acrylic acid) (PAA) shell of polymeric micelles due to ionic interaction between PAA and Fe ions. The negatively charged PAA also a platform to bind positively charged drug molecules. The hydrophilic poly(ethylene glycol) (PEG) corona stabilizes the micelles composites. The multifunctional polymeric micelles were well characterized by using different tools and techniques: dynamic light scattering, transmission electron microscope, UV–visible spectrophotometer, fluorescence spectroscope, and magnetometer.

Considerations Regarding the Dynamic Behavior of Composite Sandwich Bars with Polystyrene Core Reinforced with Fiber-Glass

In this paper some sandwich bars made from classical materials (polystyrene core, glass fiber) but combined in order to obtain an original material, are made. For these new sandwich bars, some dynamic parameters are studied, such as: damping factors per unit mass and length, eigen frequency.

Dynamics of Soft and Hairy Polymer Nanoparticles in a Suspension by NMR Relaxation.

The design of surface-modified functional nanoparticles (NPs) is used to control the properties of the NPs and the NP/environment interactions. The efficient control of the final behavior of the NPs demands a comprehensive understanding of the resulting system. This is particularly challenging for systems with an architecture of the type polymer core–polymer canopy. In such systems, one of the key parameters influencing the behavior of the NPs is the local dynamics of the polymer canopy. However, because the grafting points of the canopy are experiencing their own local dynamics, predicting the final behavior of such systems is difficult. To get a deeper understanding of NPs made of a soft and swollen polymer core and a swollen polymer canopy, we prepared a library of hairy NPs made of a polystyrene (PS) core and a canopy of grafted poly(methyl acrylate) (PMA) chains. The softness of the PS core and the thickness of the PMA canopy were controlled, and the behavior and dynamics of the soft and hairy PS–PMA NPs in suspension were measured by 1H NMR relaxation and dynamic light scattering. It was observed that the rigid PS core slowed down the subsegmental dynamics of the PMA chains, while thick PMA canopies accelerated the relaxation of the PS core. The dynamics of the NPs in suspension was the result of the interplay between the PS core and the PMA canopy.

Core\u2013shell polymeric nanoparticles co-loaded with photosensitizer and organic dye for photodynamic therapy guided by fluorescence imaging in near and short-wave infrared spectral regions

BackgroundBiodistribution of photosensitizer (PS) in photodynamic therapy (PDT) can be assessed by fluorescence imaging that visualizes the accumulation of PS in malignant tissue prior to PDT. At the same time, excitation of the PS during an assessment of its biodistribution results in premature photobleaching and can cause toxicity to healthy tissues. Combination of PS with a separate fluorescent moiety, which can be excited apart from PS activation, provides a possibility for fluorescence imaging (FI) guided delivery of PS to cancer site, followed by PDT.ResultsIn this work, we report nanoformulations (NFs) of core–shell polymeric nanoparticles (NPs) co-loaded with PS [2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a, HPPH] and near infrared fluorescent organic dyes (NIRFDs) that can be excited in the first or second near-infrared windows of tissue optical transparency (NIR-I, ~ 700–950 nm and NIR-II, ~ 1000–1350 nm), where HPPH does not absorb and emit. After addition to nanoparticle suspensions, PS and NIRFDs are entrapped by the nanoparticle shell of co-polymer of N-isopropylacrylamide and acrylamide [poly(NIPAM-co-AA)], while do not bind with the polystyrene (polySt) core alone. Loading of the NIRFD and PS to the NPs shell precludes aggregation of these hydrophobic molecules in water, preventing fluorescence quenching and reduction of singlet oxygen generation. Moreover, shift of the absorption of NIRFD to longer wavelengths was found to strongly reduce an efficiency of the electronic excitation energy transfer between PS and NIRFD, increasing the efficacy of PDT with PS-NIRFD combination. As a result, use of the NFs of PS and NIR-II NIRFD enables fluorescence imaging guided PDT, as it was shown by confocal microscopy and PDT of the cancer cells in vitro. In vivo studies with subcutaneously tumored mice demonstrated a possibility to image biodistribution of tumor targeted NFs both using HPPH fluorescence with conventional imaging camera sensitive in visible and NIR-I ranges (~ 400–750 nm) and imaging camera for short-wave infrared (SWIR) region (~ 1000–1700 nm), which was recently shown to be beneficial for in vivo optical imaging.ConclusionsA combination of PS with fluorescence in visible and NIR-I spectral ranges and, NIR-II fluorescent dye allowed us to obtain PS nanoformulation promising for see-and-treat PDT guided with visible-NIR-SWIR fluorescence imaging.

Dual-emission hydrogel nanoparticles with linear and reversible luminescence-response to pH for intracellular fluorescent probes

A type of dual-emission probe with highly recognizable luminescence-response to pH has been designed. For the prepared core-shell polymeric hydrogel nanoparticles probe (Eu(DBM)3Phen doped polystyrene (PS)-co-poly(N-isopropylacrylamide)(PNIPAM)/FITC), the red emission of inner encapsulated europium complexes Eu(DBM)3Phen is remained in the hydrophobic PS core and used as a stable reference signal. Comparingly, the green emission of outer electrostatic bonded fluorescent isothiocyanate (FITC) moieties on the hydrophilic PNIPAM shell is adjusted and acted linear and reversible luminescence-response to pH between 5.8 and 7.4 with an exact resolution of 0.1 units. As a remarkable and smart pH probe, the hydrogel nanoparticles show low biological toxicity and prolonged resistance to ions and photobleaching. Also, the probes have successfully discriminated the fluorescent imaging for cytoplasmic matrix based on different pH with minimum biologic background fluorescence. These dual-emission pH-sensitive hydrogel nanoparticles suggest potential applications in clinical medicine, such as cell imaging and disease diagnosis.

Transparent Films Made of Highly Scattering Particles.

Today, colloids are widely employed in various products from creams and coatings to electronics. The ability to control their chemical, optical, or electronic features by controlling their size and shape explains why these materials are so widely preferred. Nevertheless, altering some of these properties may also lead to some undesired side effects, one of which is an increase in optical scattering upon concentration. Here, we address this strong scattering issue in films made of binary colloidal suspensions. In particular, we focus on raspberry-type polymeric particles made of a spherical polystyrene core decorated by small hemispherical domains of acrylate with an overall positive charge, which display an unusual stability against aggregation in aqueous solutions. Their solid films display a brilliant red color due to Bragg scattering but appear completely white on account of strong scattering otherwise. To suppress the scattering and induce transparency, we prepared films by hybridizing them with oppositely charged PS particles with a size similar to that of the bumps on the raspberries. We report that the smaller PS particles prevent raspberry particle aggregation in solid films and suppress scattering by decreasing the spatial variation of the refractive index inside the film. We believe that the results presented here provide a simple strategy to suppress strong scattering of larger particles to be used in optical coatings.

A comparative study of the self-assembly of achiral and chiral hairy nanoparticles with polystyrene cores and poly(2-hydroxyethylmethacrylate) hairs.

Hairy nanoparticles with polystyrene cores (PS cores) and poly(2-hydroxyethylmethacrylate) (PHEMA) shells were synthesized by combining living anionic polymerization and atom transfer radical polymerization (ATRP). The structural characterization was carried out by FT-IR and NMR spectroscopy (1H NMR, 13C NMR, APT 13C NMR and 1H 13C HMQC). The thermal stability of the PS cores was not affected by grafting PHEMA on their surfaces. A differential scanning calorimetry (DSC) thermogram of the HNPs showed two distinct transition temperatures indicating microphase separation. Chiral HNPs were prepared by inducing chirality in the achiral HNPs by complexation with R- or S-mandelic acid. The circular dichroism (CD) spectroscopy of complexes of the HNPs/R- or S-mandelic acid indicated the formation of enantiomeric chiral structures. The self-assembled structures formed from the achiral HNPs show different surface morphologies, porous and zigzag, dependent on the solvents used. Blends of polystyrene functionalized with hydroxyl groups and PHEMA show different morphology and thermal properties compared with the core–shell HNP system. The chiral HNPs self-assembled into donut like structures or toroids with sizes in the range between 200 to 5000 nm. The study suggests that chirality can be utilized to develop interesting self-assembled structures.

Diblock Copolymer Core–Shell Nanoparticles as Template for Mesoporous Carbons: Independent Tuning of Pore Size and Pore Wall Thickness

Latex templating using core-shell particles represents a unique opportunity to design mesoporous carbons with a high level of control on textural properties. This new class of organic colloid templates is synthesized by polymerization-induced self-assembly (PISA) in which a solvophilic poly(hydroxyethyl acrylate) (PHEA) homopolymer is chain extended with a solvophobic polystyrene (PS) via a photomediated reversible-addition-fragmentation-transfer (RAFT) polymerization. The resultant PHEA-b-PS diblock copolymer nanoparticles exhibit a PS core stabilized by a PHEA shell, with two blocks characterized by a low molecular weight dispersity (1.1-1.3) and an adjustable degree of polymerization (DP). The core-shell structured nanoparticles are used as soft template for the formation of mesostructured carbons from phloroglucinol and glyoxylic acid in methanol solution. A micro- and mesostructured cellular foam is obtained having uniform, interconnected, and narrowly distributed mesopores ranging between 15 and 30 nm in diameter, a specific surface area up to 719 m2 g-1, and a total pore volume of (0.4-1.3) cm3 g-1. The mesopore size can be controlled by adjusting the diameter of the PS core (16-29 nm), while the wall thickness can be tailored independently by varying the size of the solvated PHEA shell (5-25 nm). An increase of PHEA block's DP from 25 to 85 gradually extends the stabilizing shell dimension, thus increasing the wall thickness up to 10 nm, and causing the shift from interconnected to isolated mesopores. By comparison, much thinner walls (2-3 nm) are obtained with conventional latex templates such as polystyrene nanoparticles or colloidal silica. Decreasing PHEA DP to 17 induces the formation of copolymer vesicles that can be used as template to create mesoporous carbons with nonspherical mesopores.

Thermodynamic Analysis of the Uptake of a Protein in a Spherical Polyelectrolyte Brush.

A thermodynamic study of the adsorption of Human Serum Albumin (HSA) onto spherical polyelectrolyte brushes (SPBs) by isothermal titration calorimetry (ITC) is presented. The SPBs are composed of a solid polystyrene core bearing long chains of poly(acrylic acid). ITC measurements done at different temperatures and ionic strengths lead to a full set of thermodynamicbinding constants together with the enthalpies and entropies of binding. The adsorption of HSA onto SPBs is described with a two-step model. The free energy of binding ΔGb depends only weakly on temperature because of a marked compensation of enthalpy by entropy. Studies of the adsorbed HSA by Fourier transform infrared spectroscopy (FT-IR) demonstrate no significant disturbance in the secondary structure of the protein. The quantitative analysis demonstrates that counterion release is the major driving force for adsorption in a process where proteins become multivalent counterions of the polyelectrolyte chains upon adsorption. A comparison with the analysis of other sets of data related to the binding of HSA to polyelectrolytes demonstrates that the cancellation of enthalpy and entropy is a general phenomenon that always accompanies the binding of proteins to polyelectrolytes dominated by counterion release.

Investigation of thermal and mechanical properties of styrene–butadiene rubber nanocomposites filled with SiO2–polystyrene core–shell nanoparticles

The present study investigates the effect of SiO2–polystyrene core–shell nanoparticles on properties of styrene–butadiene rubber nanocomposites. Meanwhile, SiO2–polystyrene core–shell nanoparticles were synthesized under controlled ultrasound assisted microemulsion technique. Further, as-synthesized SiO2–polystyrene nanoparticles were subjected to various characterization techniques, such as X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, and Fourier transform infrared spectroscopy to know its size, shape, and presence of functional groups. The average diameter of SiO2–polystyrene nanoparticles was found to be ∼45 nm. SiO2–polystyrene nanoparticles were reinforced in styrene–butadiene rubber using two-roll mill and molded on compression molding machine, which then subjected to various testings (X-ray diffraction, field emission scanning electron microscope, thermogravimetric analysis, and universal testing machine). Moreover, the crosslinking density was investigated using solvent sorption technique. The properties of styrene–butadiene rubber nanocomposites were found to be improved with increasing amount of SiO2–polystyrene nanoparticles (2.0 wt%) and decreases subsequently (2.5 wt%). This enhancement in properties was due to uniform dispersion of core–shell nanoparticles with embedded chains of rubber. Also this enhancement in properties was due to smooth surface of core–shell nanoparticles (2.0 wt%) and decreases subsequently at higher amount of loading (2.5 wt%). However, the minimal crosslinkage leads to more solvent sorption, which leads to increase in average molecular weight. This decrement in the crosslinkage density with increase in average molecular weight was due to voids or free volume inside the matrix, which allows the solvent to get penetrated inside the matrix. This effect was not due to styrene–butadiene rubber matrix but due to shell of polystyrene over SiO2.

Clustering of asymmetric dumbbell-shaped silica/polystyrene nanoparticles by solvent-induced self-assembly

We report a quite simple strategy to assemble silica/polystyrene dumbbell-shaped nanoparticles into clusters with an aggregation number from two to more than 30. The polystyrene lobe serves as a patch that is made sticky and ready to merge with similar ones when the dumbbells are dispersed in an ethanol/DMF mixture. Thanks to transmission electron microscopy experiments, we describe qualitatively and quantitatively the influence of several experimental parameters such as the solvent quality, i.e. DMF fraction, and the patch-to-particle size ratio. We show that the DMF fraction range (30–50 vol%) for the sticky regime can be extended if the incubation process is completed by a centrifugation step. We also demonstrate an unexpected evolution in the average aggregation number with the patch-to-particle size ratio that may be explained by the molar mass distribution within the polystyrene core of the clusters. Lastly, we show that this assembly route may be extended to gold-coated clusters.

Polystyrene-supported dendritic mesoporous silica hybrid core/shell particles: controlled synthesis and their pore size-dependent polishing behavior

This work described a straightforward synthetic route to fabricating polymer/silica hybrid particles with controllable architectures and their advantages as abrasives. The poly(vinylpyrrolidone)-modified and divinyl benzene cross-linked polystyrene (PS) cores were synthesized via a developed soap-free emulsion polymerization, and the outer dendritic-like mesoporous silica (D-mSiO2) shells were coated onto the cores using an oil–water biphase approach combined with a selective removal of hexadecyltrimethylammonium bromide templates. The resulting core/shell PS/D-mSiO2 samples were characterized by SEM, TEM, XRD, FTIR, and nitrogen adsorption/desorption, offering comprehensive information on the composition, structure, morphology, pore size, shell thickness, and surface area. The pore size of D-mSiO2 can be controlled within the range of 3–9 nm by varying the upper oil phases, which serve as swelling agents to enlarge the mesochannels. The PS/D-mSiO2 particles can be used as novel polishing abrasives and present superior surface quality (0.16 ± 0.02 and 0.26 ± 0.03 nm of root-mean-square roughness) compared to the commercial solid SiO2 ones (0.54 ± 0.05 nm). Moreover, the PS/D-mSiO2 hybrids with an enlarged pore size result in an inferior structural stability, which is important for final surface finish and removal rate. The presented results provide not only a strategy for preparing PS/D-mSiO2 core/shell particles with tunable pore sizes, but also a regulation that can be applied to prepare other core/shell hybrids with dendritic-like mesosilica shells.

Fabrication of functionalized magnetic microspheres based on monodispersed polystyrene for quantitation of allyl-benzodioxoles coupled with gas chromatography and mass spectrometry

Monodispersed magnetic microspheres were synthesized by the magnetization of the aminized polystyrene cores and the subsequent polymerization of allyl glycidyl ether, divinylbenzene and N-vinyl-2-pyrrolidone, which exhibited excellent monodispersity in aqueous solution and high efficiency for allyl-benzodioxoles extraction. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM) were employed to characterize the composites. Coupled with gas chromatography-mass spectrometry (GC–MS), a sensitive and simple magnetic solid phase extraction (MSPE) procedure based on the prepared microspheres was established for determination of allyl-benzodioxoles in cola-flavoured drinks. The factors affecting the extraction procedure, such as pH value, adsorbent amount, adsorption time, desorption solution and desorption time were optimized. The developed method was characterized by a high recovery (spiked at 5 μg L−1, 25 μg L−1 and 250 μg L−1), a low detection limit (0.05 μg L−1 for safrole and 0.08 μg L−1 for myristicin), a good linearity (correlation coefficients higher than 0.9990 for both) and a satisfactory repeatability (relative standard deviation below 3.7% for both, n = 3). The approach proposed here was confirmed to be fast and reliable for quantitative analysis of allyl-benzodioxoles in cola samples, especially at a trace level.

Shell Architecture Strongly Influences the Glass Transition, Surface Mobility, and Elasticity of Polymer Core-Shell Nanoparticles.

Despite the growing application of nanostructured polymeric materials, there still remains a large gap in our understanding of polymer mechanics and thermal stability under confinement and near polymer–polymer interfaces. In particular, the knowledge of polymer nanoparticle thermal stability and mechanics is of great importance for their application in drug delivery, phononics, and photonics. Here, we quantified the effects of a polymer shell layer on the modulus and glass-transition temperature (Tg) of polymer core–shell nanoparticles via Brillouin light spectroscopy and modulated differential scanning calorimetry, respectively. Nanoparticles consisting of a polystyrene (PS) core and shell layers of poly(n-butyl methacrylate) (PBMA) were characterized as model systems. We found that the high Tg of the PS core was largely unaffected by the presence of an outer polymer shell, whereas the lower Tg of the PBMA shell layer decreased with increasing PBMA thickness. The surface mobility was revealed at a temperature about 15 K lower than the Tg of the PBMA shell layer. Overall, the modulus of the core–shell nanoparticles decreased with increasing PBMA shell layer thickness. These results suggest that the nanoparticle modulus and Tg can be tuned independently through the control of nanoparticle composition and architecture.