Composite materials based on poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels and calcium carbonate

Abstract

The synthesis of complex functional materials with thermo-and pH-sensitive tunable properties based on poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels with different porosities and pH-sensitive and biocompatible calcium carbonate (CaCO 3 ) was investigated. To control the composites characteristics, two hydrogles with the same chemical composition but different porosities were used, as well as different methods for crystal growth, namely, the adding protocol of inorganic partners (rapid mixing or alternate dipping) or the carbonate source. The morphology of the new composites was investigated by scanning electron microscopy and the polymorphs content by Fourier transform infrared spectroscopy, as compared to unmodified hydrogels. Information on the interface between organic/inorganic materials, the radii of gyration of the scattering objects, their fractal dimension, and CaCO 3 porosity characteristics were obtained by small-angle X-ray scattering.

Hydrophobic Composites Designed by a Nonwoven Cellulose-Based Material and Polymer/CaCO3 Patterns with Biomedical Applications

“…Several studies dealt with the selective nucleation of calcium carbonate using chemically modified substrates (acting as templates), − aiming to obtain hydrophobic materials. − For instance, Aizenberg and co-workers succeeded in performing the ordered crystallization of calcite using micropatterned self-assembled monolayers on a metal substrate. , Our previous studies on hydrogels or gel-like ion exchangers showed that the surface crystal growth depends on the functional groups at the material surface (acidic or amine) and also by the applied methods for crystal growth, namely, the adding protocol of inorganic partners (rapid mixing, alternate dipping, or diffusion) or the carbonate source (Na 2 CO 3 or dimethyl- or diethylcarbonate). ,, The ammonium diffusion method led to more uniform CaCO 3 /cryogel composites with less excess crystals, as compared to the rapid mixing or alternate dipping in precursor solutions …”

Superparamagnetic Composites Based on Ionic Resin Beads/CaCO3/Magnetite

“…[4,5] The retention of metalc ationsc an occur by ion exchange-using cation exchangers or strong base anion exchangers, if metal cations are as complex anions or the conditions to form these anionsa re met-or by chelating processes, when the ion exchangers contain one or more electron-donor elements (N, S, O, and P), such as amine, thiol, thiouronium, iminodiacetate, aminophosphonate, amidoxime groups, etc. These molecules can be insoluble organic matricest hat generate ap ropere nvironmenti nw hich crystallization can occur [8,9] or soluble organic additives that can vary from small molecules to large polymers, and can generate crystalsw ith complex morphologies and composite structures and superior mechanical properties. [7] In nature,b iominerals are formedi ng el-like extracellular networks that use supramolecular assemblies of biomolecules to control the process.…”

“…These molecules can be insoluble organic matricest hat generate ap ropere nvironmenti nw hich crystallization can occur [8,9] or soluble organic additives that can vary from small molecules to large polymers, and can generate crystalsw ith complex morphologies and composite structures and superior mechanical properties. [9] To control the composites characteristics, differentm ethods for crystal growth were used, namely the adding protocol of inorganic partners (rapid mixing or alternate dipping) or the carbonate source (Na 2 CO 3 ,dimethyl-or diethylcarbonate). Ar ange of different model systems were used as synthetic matricesfor CaCO 3 crystallization.…”

“…In nature, biominerals are formed in gel‐like extracellular networks that use supramolecular assemblies of biomolecules to control the process. These molecules can be insoluble organic matrices that generate a proper environment in which crystallization can occur or soluble organic additives that can vary from small molecules to large polymers, and can generate crystals with complex morphologies and composite structures and superior mechanical properties …”

“…A range of different model systems were used as synthetic matrices for CaCO 3 crystallization. An example is the synthesis of complex functional materials with thermo‐ and pH‐sensitive tunable properties based on a poly( N ‐isopropylacrylamide‐ co ‐methacrylic acid) hydrogel and pH‐sensitive and biocompatible CaCO 3 . To control the composites characteristics, different methods for crystal growth were used, namely the adding protocol of inorganic partners (rapid mixing or alternate dipping) or the carbonate source (Na 2 CO 3 , dimethyl‐ or diethylcarbonate).…”