Determination of the Ideal Surfactant Concentration in Miniemulsion Polymerization

Hecht, Lena L.; Schoth, Alexander; Muñoz‐Espí, Rafael; Javadi, Aliyar; Köhler, Karsten; Miller, R.; Landfester, Katharina; Schuchmann, Heike P.

doi:10.1002/macp.201200583

Cited by 35 publications

(32 citation statements)

References 51 publications

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“…For up to 20 wt% of MPS-functionalized silica, the composite particles have only a small number of silica nanoparticles close to the surface and they are well distributed. However, small empty particles resulting from secondary nucleation can be observed in all samples, which is consistent with previous results [43]. With more than 20 wt% of silica particles, aggregates inside the monomer droplets start to form, resulting in a heterogeneous distribution of the inorganic particles in the monomer phase.…”

Section: Encapsulation Of Hydrophobized Silica Particlessupporting

confidence: 93%

Structure control in PMMA/silica hybrid nanoparticles by surface functionalization

et al. 2014

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Hydrophilic silica particles need to be hydrophobized to be encapsulated in a polymeric environment, which can be achieved by different methods. We report on the relationship between different hydrophobization techniques of silica and the final structure of poly(methyl methacrylate)/silica hybrid nanoparticles obtained by miniemulsion polymerization. Hydrophobization by cetyltrimethylammonium chloride (CTMA-Cl) uses the ionic interaction between the positively charged ammonium salt and the negatively charged silica surface, as shown by isothermal titration calorimetry. In this case, the interaction between polymer and silica surface needs to be enhanced, so 4-vinylpyridine (4-VP) was used as a co-monomer. Alternatively, the condensation reactions of 3-methacryloxypropyltrimethoxysilane (MPS) and octadecyltrimethoxysilane (ODTMS) were used to provide a covalent bond to the silica surface. The condensation reaction of the trimethoxysilane groups onto the silica surface was proven by Fourier transform infrared spectroscopy and thermogravimetric analysis. Hybrid nanoparticles were successfully formed with silica particles functionalized with the different functionalization agents. However, the structure of the resulting hybrid particles (i.e., the distribution of the silica particles within the polymer matrix) depends on the agent. The MPS-functionalized silica particles copolymerize with poly(methyl methacrylate), leading to a fixation of the silica particles inside the polymer and to a homogeneous distribution. The CTMA-Cl-and ODTMSfunctionalized silica particles cannot copolymerize, but aggregate at the interface, leading to a Janus-like structure.

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Section: Encapsulation Of Hydrophobized Silica Particlessupporting

confidence: 93%

Structure control in PMMA/silica hybrid nanoparticles by surface functionalization

et al. 2014

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“…The CMCs of P1 (PG 36 -b-PAGE 14 , CMC = 0.16 mg mL −1 ; Figure S3 in the Supporting Information) and P4 (PG 35 -b-PtBuGE 15 , CMC = 0.07 mg mL −1 ; Figure S3 in the Supporting Information) were in a comparable range to nonionic PEG-based surfactants (e.g., Lutensol AT50 (C 16-18 -alkylblock-PEG 50 ), CMC = 0.03 mg mL −1 ). [21] The observed CMC of P5 (PG 28 -b-PtBuGE 31 , CMC = 0.63 mg mL −1 ) was higher compared to P1 and P4, maybe due to similar hydrophilic to hydrophobic block length ratios of P5.…”

Section: Surface Active Propertiesmentioning

confidence: 90%

Polyglycerol Surfmers and Surfactants for Direct and Inverse Miniemulsion

Wald

Simon

Dietz

et al. 2017

Macromolecular Bioscience

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studied as promising surfactants for emulsions. [10] Furthermore, vinyl-terminated polyglycerols were used as surfmers to synthesize stable polystyrene (PS) microspheres for medical diagnostics for possible postfunctionalization with proteins. [11,12] Hyperbranched and linear surfmers based on polyglycerols were additionally used to generate stable PS nanoparticles. [13] However, for the miniemulsion approach only less multifunctional PG-based surfactants or surfmers are known.Here, we use the versatility of the anionic polymerization of glycidyl ethers to prepare a series of multifunctional (additional OH-groups or polymerizable CC-groups) surfactants with adjustable hydrophiliclipophilic balance (HLB) that allows the stabilization of direct (oil-in-water) or inverse (water-in-oil) (mini)emulsions or can be used simultaneously for both systems.Two known orthogonal protection strategies, reported by Möller and coworkers, [14] were used to synthesize linear completely poly glycerol-based block copolymers as surfactants or surfmers for direct, inverse, or both types of miniemulsions (Scheme 1). The orthogonal-protected block copolymers were generated by anionic ring-opening polymerization in bulk using ethoxyethyl glycidyl ether (EEGE) and allyl glycidyl ether (AGE) or tert-butyl glycidyl ether (tBuGE) with defined block length ratios to tune their HLB. After acidic hydrolysis of the acetal groups, the water-soluble allyl-functionalized PG block copolymers were established as surfmers in the radical miniemulsion poly merization of styrene to generate polystyrene nanoparticles with decreased protein adsorption behavior due to incorporated PG surfactants (Scheme 1). In addition, oil-soluble allyl-functionalized block copolymers were introduced as surfmers to produce polyurea/urethane nanocapsules by interfacial polyaddition reactions of hydroxyethyl starch (HES) with toluene diisocyanate (TDI) (Scheme 1). [15] Furthermore, the allyl-protection groups on the polyurethane nanocarrier surface were utilized for surface functionalization by thiol-ene addition in water. For this purpose, the nanocarriers were transferred into water including a tert-butyl-protected poly glycerol block copoly mer. The tert-butyl-protected polyglycerol block copolymers were applied as surfactant to generate polystyrene nanoparticles in direct miniemulsions for comparison with the allyl-protected surfmer and in inverse miniemulsions to produce stable poly(hydroxyethyl methacrylate) (PHEMA)

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“…Possible explanations for the different nucleation mechanisms depending on the type of surfactant are the differences in dynamic adsorption behavior and equilibrium concentration in the bulk phase, as discussed in [52].…”

Section: Determination Of the Ideal Surfactant Concentrationmentioning

confidence: 99%

“…The adsorption isotherms of sodium dodecyl sulfate (SDS) and Lutensol AT50 at the water/MMA interface were measured and fitted with different adsorption models (see [52] for details). The best fit results are shown in Table 2.…”

Section: Determination Of the Ideal Surfactant Concentrationmentioning

confidence: 99%

Continuous Preparation of Polymer/Inorganic Composite Nanoparticles via Miniemulsion Polymerization

Merkel

Hecht

Schoth

et al. 2015

Colloid Process Engineering

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Composite nanostructured particles can be produced by polymerization of monomer miniemulsion droplets loaded with inorganic nanoparticles. The article gives an overview on the development of a scalable continuous process for the production of such hybrid nanoparticles via miniemulsion polymerization. Different possibilities for the necessary surface modification of the inorganic material are discussed in detail. Furthermore, the influence of the surfactant concentration on the droplet size after emulsification as well as on the nucleation mechanisms during polymerization is highlighted. Possible process routes for the emulsification of the nanoparticle-loaded monomer phase are compared taking into account different process and material parameters, such as energy consumption, abrasion, dispersed phase viscosity, inorganic particle load and size, and morphology of the resulting hybrid particles. The possibility of an industrial implementation via an integrated high pressure homogenization process and a subsequent continuous polymerization are presented.

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Determination of the Ideal Surfactant Concentration in Miniemulsion Polymerization

Cited by 35 publications

References 51 publications

Structure control in PMMA/silica hybrid nanoparticles by surface functionalization

Structure control in PMMA/silica hybrid nanoparticles by surface functionalization

Polyglycerol Surfmers and Surfactants for Direct and Inverse Miniemulsion

Continuous Preparation of Polymer/Inorganic Composite Nanoparticles via Miniemulsion Polymerization

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