PCL by Hotstage TM-AFM

Crystallization of PCL by Hotstage TM-AFM Sample Preparation Solution Casting 

We follow an example published by Beekmans and Vancso [65]. PCL with a molar mass of 55,000 g/mol (e.g., Aldrich) is purified by precipitation from chloroform solution into methanol. Films are cast from 3% solutions in chloroform on cleaned glass slides at 50°C followed by drying in air at the same temperature, and in vacuum at room temperature for 1 day. The sample is mounted to the AFM hot 

4 Polymer Surface and Interface Properties and (Dynamic) Processes 

Isothermal crystallization experiments are performed by melting the PCL in the AFM apparatus at 100°C for 10 min, followed by quenching to the desired crystallization temperature. Care must be taken that the AFM tip is not accidentally in contact with the polymer film and is engaged only after reaching the desired temperature. 

We use a standard tapping/intermittent contact mode set-up, which is started as described in Sect. 3.2 in Chap. 3. The operation frequency and amplitude are adjusted to v at 0.85 A0 and 200 nm, respectively. Because of the stickiness of the polymer melt, this high amplitude is advisable to avoid permanent tip-sample contact/adher-ence during the scans. Immediately prior to engaging, the phase signal is zeroed. The crude and fine engagement procedures are carried out as described in Chap. 2. After the successful engagement, the operation point must be carefully adjusted. 

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