Synthesis of raspberry-like organic-inorganic hybrid nanocapsules via pickering miniemulsion polymerization: Colloidal stability and morphology

2011 ◽  
Vol 49 (11) ◽  
pp. 2382-2394 ◽  
Author(s):  
Zhihai Cao ◽  
Anika Schrade ◽  
Katharina Landfester ◽  
Ulrich Ziener
Keyword(s):  
Colloidal Stability ◽  
Miniemulsion Polymerization ◽  
Inorganic Hybrid

Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization in Miniemulsion Based on In Situ Surfactant Generation

2011 ◽  
Vol 64 (8) ◽  
pp. 1033 ◽  
Author(s):  
S. R. Simon Ting ◽  
Eun Hee Min ◽  
Per B. Zetterlund
Keyword(s):  
Potassium Hydroxide ◽  
Colloidal Stability ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Miniemulsion Polymerization ◽  
High Energy ◽  
Reversible Addition ◽  
Raft Agent ◽  
Surface Active

Reversible addition–fragmentation chain transfer (RAFT) polymerization of styrene has been implemented in aqueous miniemulsion based on the in situ surfactant generation approach using oleic acid and potassium hydroxide in the absence of high energy mixing. The best results were obtained using the RAFT agent 3-benzylsulfanyl thiocarbonyl sufanylpropionic acid (BSPAC), most likely as a result of the presence of a carboxylic acid functionality in the RAFT agent that renders it surface active and thus imparts increased colloidal stability. Stable final miniemulsions were obtained with no coagulum with particle diameters less than 200 nm. The results demonstrate that the RAFT miniemulsion polymerization of styrene employing the low energy in situ surfactant method is challenging, but that a system that proceeds predominantly by a miniemulsion mechanism can be achieved under carefully selected conditions.

Experimental Fabrication and Property Research of Thermo-Sensitive Organic-Inorganic Hybrid Nano-Microcapsule

2014 ◽  
Vol 886 ◽  
pp. 75-79
Author(s):  
Qin Fang Lu ◽  
Yue Shang ◽  
Guo Rong Shan
Keyword(s):  
Critical Temperature ◽  
Penetration Rate ◽  
Miniemulsion Polymerization ◽  
Inorganic Hybrid ◽  
Propyl Methacrylate ◽  
Isopropyl Acrylamide ◽  
Cresol Red

A thermo-sensitive organic-inorganic hybrid nanomicrocapsule was synthesized by miniemulsion polymerization through introducing N-isopropyl acrylamide (NIPAM) monomer to the copolymer of styrene that coat around the octane droplet and 3-trimethoxysil propyl methacrylate (MPS). The penetration and releasing behavior of cresol red in this nanomicrocapsule nearby the critical temperature was investigated with ultravioletvisible spectroscopy. The results showed that both the introduction of NIPAM monomer and the temperature affect the loading and releasing of cresol red in nanomicrocapsule and the microcapsule exhibited a certain penetration rate above the critical temperature, but the penetration was inconspicuous below the critical temperature, denoting that this nanomicrocapsule could realize on-off type of environmental thermo-sensitive controlled absorption and release.

Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3353-3360
Author(s):  
Susana Helena Arellano Ramírez ◽  
Perla García Casillas ◽  
Christian Chapa González
Keyword(s):  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Infrared Spectrometry ◽  
Ammonium Bromide ◽  
Chloroauric Acid ◽  
Vis Spectroscopy ◽  
Seed Mediated ◽  
Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

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