Hydrophilic/hydrophobic copolymers adsorption onto

Balazs and Lewandowski (1990) have performed simulations of the adsorption of triblock copolymers onto a planar surface, and examined the conformations of the adsorbed chains. Monte Carlo simulations were performed of the motion of hydrophilic-hydrophobic chains on a cubic lattice. These simulations revealed a complex structure in the interfacial region due to the self-assembly of chains, driven by the solvent-incompatible block, reducing adsorption onto the surface. The influence on the surface coverage of length of the hydrophilic segement, polymer concentration, interaction energy between hydrophilic block and the... 

The following protocol for passive adsorption is based on methods reported for use with hydrophobic polymeric particles, such as polystyrene latex beads or copolymers of the same. Other polymer particle types also may be used in this process, provided they have the necessary hydrophobic character to promote adsorption. For particular proteins, conditions may need to be optimized to take into consideration maximal protein stability and activity after adsorption. Some proteins may undergo extensive denaturation after immobilization onto hydrophobic surfaces therefore, covalent methods of coupling onto more hydrophilic particle surfaces may be a better choice for maintaining native protein structure and long-term stability. 

A change in the hydrophilic nature of the polymer surface on irradiation of poly-(p-phenylazoacrylanilide) (PAAn) or its copolymer with HEMA may be used to control the adsorption — desorption behavior of proteins or organic substances onto the polymer [49]. Adsorption of lysozyme onto the copolymer of p-phenylazo-acrylanilide and HEMA was foimd to decrease from 4.6 eg to 1.8 eg per gram of adsorbent on ultraviolet irradiation, which induces the isomerization from the trans to the cis form. The decrease in adsorption ability upon ultraviolet irradiation is explained by a reduction of the hydrophobic interaction between the protein and the polymer, which results from the appearance of hydrophilic cw-form azobenzene on the surface. 

In order to impart hydrophilicity to neutral hydrophobic hypercrosslinked adsorbing resin CHA-101 (also obtained by post-crosslinking chloromethylated styrene-DVB copolymer), the latter was subjected to heating at 100°C within 12h in nitrobenzene in the presence of FeCb (6g per 30 g of sorbent beads) [92]. The resulting resin, NDA-702, was stated to be directly wetted by water. A comparative study of dimethyl phthalate adsorption at 10°C onto NDA-702, XAD-4, and AC-750 activated carbon showed that the sorbents take 500, 400, and 300 mg/g of the ester, respectively. The loading capacity of the sorbents decreases by 50-100 mg/g with temperature rising to 40°C. 

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