PS-b-P4VP block copolymers were solution-blended with polyacrylic acid (PAA) and polyethylene oxide (PEO)

respectively

followed with spin-coating on glass substrates.The resulting thin films were imaged by atomic force microscope (AFM) to investigate the tuning effects of the two homo-polymers on the micro-phase separation morphologies of PS-b-P4VP thin films.The results showed that thermodynamic repulsion between P4VP and PS segments was enhanced due to strong interaction between PAA and P4VP by hydrogen bonds.In the thin film with 10% (mass) of PAA

micro-phase separation morphology with cylindrical PS micro-domains dispersed regularly into P4VP/PAA matrix was observed.The cylindrical PS micro-domains oriented perpendicularly to the film surface.In the PS-b-P4VP/PEO thin films

micro-phase separation morphologies with PS as matrix and cylindrical micro-domains of PEO/P4VP oriented perpendicularly to the film surface were formed.The top of PEO/P4VP cylindrical micro-domains was not covered by PS segments

leading to the holes on the surface of the film.Also

cone-shaped projections could be found at the bottom of holes due to crystallization of PEO segments inside PEO/P4VP micro-domains.With the increase of PEO content

the size of holes increased and the cone-shaped projections at the bottom of holes became more apparent.