Phases in Blends of PMMA and PB

Identification of Phases in Blends of PMMA and PB Sample Preparation Spincoating of Blends 

Blends, e.g. 80 20, of poly (methyl methacrylate) (PMMA, weight average molar mass, Mw, of 15,000 g/mol) and polybutadiene (PB, with Mw 420,000 g/mol) (e.g. from Aldrich) are prepared by mixing solutions of a mass fraction of PMMA of 0.02 in toluene and mass fraction of PB of 0.02 in toluene in a ratio of 8 2 followed by spin-coating onto pre-cleaned silicon wafers. Following the spinning, the samples are treated for 24 h at ambient temperatures under vacuum to remove residual solvent. Pieces of the blend-covered silicon wafer are glued to the sample holder disc and inserted into the AFM. 

Using the standard TM-AFM procedures (3.2.1), the free surface of the blend thin films can be investigated. Owing to the softness and adherent properties of the PB phase, it is advisable to increase the rms amplitude of the free cantilever oscillation sufficiently. 

A typical dual height and phase image of a PMMA-PB 80-20 blend is shown in Fig. 3.60. The height differences observed are small, typically only few nanometers 

Data type Height Data type Phase 

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