Hybrid inorganic-organic nano- and microcomposites based on silica sols and synthetic polyelectrolytes

Abstract

Hybrid inorganic-organic nanocomposites comprising inorganic nanoparticles and functional polymers are novel and unique class of nanomaterials that synergistically combine and enhance the best properties of inorganic and organic polymers [1][2][3][4]. The potential application fields of such hybrids can include specialty coatings, membranes, sensors, biomaterials, drug delivery systems, catalysts etc. The most common principle concepts of incorporation of inorganic nanoparticles into polymer matrix and the resulting properties of such materials have been reviewed by authors [5][6][7]. Classification of polymer/silicate nanocomposites based on synthetic techniques was suggested in [8]. Although titanium [9,10] and aluminum [11] oxides have been utilized as the inorganic components interacting with functional polymers, the colloid silica due to easy preparation by sol-gel technology [12] is one of the promising inorganic polymeric materials that interacts with polyelectrolytes and forms, so called interpolyelectrolyte complexes (IPEC) -products of interaction of two oppositely charged polyelectrolytes [13][14][15][16][17] Abstract. Interaction between anionic (and cationic) colloidal particles of silica having the particles diameters 12 and 22 nm with synthetic cationic (and anionic) polyelectrolytes of various nature and structure was studied by potentiometric, conductimetric spectroturbidimetric and viscometric methods in aqueous solution. It was shown that the complexation of silica nanoparticles with linear polyelectrolytes leads to formation of mostly stoichiometric interpolyelectrolyte complexes (IPEC) which precipitate from aqueous solution. Casting of water-soluble IPEC followed by thermal treatment gives thin composite films insoluble in water while 'layer by layer' (LbL) deposition of polyelectrolyte components onto silica sols leads to formation of multilayered nano-and microcomposites. The possible mechanism of formation of LbL multilayers consisting of silica sol (SiO2) 'cores' and polyethyeleneimine-polyacrylic acid (PEI-PAA) 'shells' was suggested. It was found that in diluted aqueous solution the radius of gyration, Rg and hydrodynamic radius, Rh mean of LbL particles are independent on LbL concentration and smaller than 100 nm. The zeta potential values of LbL particles are arranged between -10 and -30 mV. The average size of LbL particles estimated by scanning electron microscopy (SEM) is in the range of 200-500 nm. Thermal treatment of LbL multilayers followed by etching of (SiO2) 'core' by HF leads to formation of a series of spherical nanocavities and blob-like microcavities. Vol.2, No.2 (2008) [101][102][103][104][105][106][107][108][109][110] Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2008 Keywords: nanomaterials, silica nanoparticles, linear polyelectrolytes, interpolyelectrolyte complexes eXPRESS Polymer Letters Experimental MaterialsColloidal particles of silica are commercial products purchased from Ludox (Grace GmbH & Co. KG, Worms, Germany) were abbr...

In-situ silica incorporated carboxymethyl tamarind: Development and application of a novel hybrid nanocomposite

“…2e) spectrum of the nanocomposite shows three different signals at −94, −101 and −111 ppm which can be assigned to (-O-) 2 Si(OH) 2 with two OH groups (Q 2 ), (-O-) 3 Si(OH) with one OH group (Q 3 ) and (-O-) 4 Si with no OH group attached to the silicon atom (Q 4 ). The spectrum is almost identical to the initial silica material, further confirming successful insertion of silica nanoparticle onto CMT backbone.…”

“…Hybrid inorganic-organic nanocomposites are novel and unique class of materials with drastically improved physico-mechanicals because of the presence of nano-sized fillers into polymer matrices [1][2][3][4] in low amount (generally less than 5 wt%). Such improvements are subject to large interfacial area of the fillers available for extensive polymer-filler interactions [1,[5][6][7].…”

Influence of the Formulation Process in Electrostatic Assembly of Nanoparticles and Macromolecules in Aqueous Solution: The Mixing Pathway

“…Electrostatic self- or coassembly , between charged nanocolloids and/or polymers to generate functional materials and surfaces has recently aroused much interest, essentially because of their potential applications in various fields, such as material science − and biology. − However, compared to the abundant work on the mechanisms, structure characterizations and functionalities, not much attention has been paid to the formulation process. Indeed, in strongly associating polymeric systems, it often takes a very long time to reach true equilibrium.…”

Influence of the Formulation Process in Electrostatic Assembly of Nanoparticles and Macromolecules in Aqueous Solution: The Interaction Pathway

“…Combining the advantageous properties of both the organic and inorganic worlds offers a great promise for engineering versatile functional structures with controlled physical and chemical attributes at the nanometer scale. This synergy will certainly trigger the emergence of a wide range of novel materials and processing techniques in various scientific and technological fields such as material science [4][5][6][7][8] and biology. [9][10][11][12][13] Compared to the abundant work on the mechanisms, structure characterizations, and functionalities, however, not much attention has been paid to the formulation process, which is a key issue for generating functional systems or devices on a large scale.…”