Synthesis, film morphology and hydrophobicity of novel fluorinated polyacrylate emulsion and solution on silicon wafer

Novel fluorinated polyacrylate emulsion (CFBDH) and solution (SFBDH) were synthesized by polymerization of dodecafluoroheptyl methacrylate (DFMA) with butyl acrylate (BA), dimethylaminoethyl methacrylate (DM) and 2-hydroxypropyl acrylate (HpA) via seeded emulsion polymerization and solution polymerization, respectively. Chemical structure, particle morphology, glass transition temperature and thermal property of resultant CFBDH and SFBDH were characterized by FT-IR, 1H NMR, TEM, DSC and TGA, respectively. The as-prepared products were utilized to treat the clean silicon wafers and form films on it, and then morphology and hydrophobicity of films were investigated by SEM, AFM, contact angle meter, etc. Results showed that the CFBDH particles had uniform spherical core–shell structure with an average diameter of 126 nm. Core–shell CFBDH film thus had two Tg and SFBDH film only had one Tg. Their thermal properties were improved. The SFBDH film seemed less level and continuous than the CFBDH film by SEM at an amplification of 1000 and the observation rule of 20 μm. However, as the observation rule decreased to 3 nm, both the CFBDH and SFBDH films were inhomogeneous and existed in a phase-separated state with many low or high peaks in AFM images. The higher bright peaks in CFBDH film were much more and distributed uniformer than those in SFBDH film, but the roughness of CFBDH film was less than that of SFBDH film, the average roughness (Rq) of the CFBDH and SFBDH films reached to 0.205 nm and 0.336 nm in 1 μm2 scanning field, respectively. In addition, contact angles on CFBDH/Sil and SFBDH/Sil surfaces separately attained 104.3° and 98.5°.

The bright needle-like peaks resulting from the phase-separated fluoroalkyl groups in core–shell CFBDH film were much more and distribute uniformer than those in SFBDH film. However, the roughness of CFBDH film was less than that of SFBDH film. In addition, hydrophobicity of CFBDH film was better than that of SFBDH film and water contact angles (WCA) on CFBDH and SFBDH films reached to 104.3̊ and 98.5̊, respectively.Figure optionsDownload as PowerPoint slideHighlights
► We synthesized novel core–shell and random fluorinated acrylate polymers.
► Film morphology and hydrophobicity of those two polymers on silicon wafer were compared.
► Film roughness of random polymer was more than that of core–shell one.
► Fluoroalkyl groups in core–shell film were much more and distributed uniformer than those in random film.
► Contact angles on core–shell and random films separately attained 104.3° and 98.5°.