Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers are used in a wide range of industrial applications from detergents to pharmaceutical materials. We have employed surface plasmon resonance (SPR) to monitor the adsorption of these materials, from aqueous solutions to a model hydrophobic surface. The effect of varying the PPO or PEO block size of the copolymer on adsorption has been investigated, and a linear increase in SPR angle shift with increasing PPO or PEO chain length is observed. The SPR angle shifts show a greater increase in SPR angle with increasing PPO block size compared to an equivalent increase in PEO block size. This has been explained by considering the effect each block has on the dielectric properties of the adsorbed polymer at the interface. The presence of micelles in solution and their influence on Pluronic adsorption has also been considered, and adsorption from micellar solutions has been determined to be dependent on the PPO content of the copolymer.

Pluronic surfactants, PEO-PPO-PEO triblock copolymers, have been investigated widely due to their protein-resistant properties in applications as coatings for implants and in controlled drug release systems. We have studied a wide range of these copolymers, varying in both PEO and PPO block size, by adsorbing them to a polystyrene surface and investigating their subsequent resistance to human serum albumin adsorption. This investigation has been carried out in real time, using surface plasmon resonance, with the surfaces subsequently visualized by atomic force microscopy. This approach has allowed determination of the effect of the lengths of the PEO and PPO polymer chains on protein resistivity. For low-molecular-weight Pluronics a significant, yet not complete, reduction in albumin adsorption has been observed whereas higher molecular weight Pluronics appear to completely inhibit adsorption within the time frame of this experiment. An increase in the PPO block size of the copolymer also appears to increase its protein resistance. This work further confirms that the binding strength of the anchoring block to the hydrophobic surface, rather than the length of the protruding hydrophilic PEO chains, determines a copolymer's protein resistance capability.