Scattering Measurements for High Throughput Materials Science Research a Alexander I. Norman,* Joa ˜o T. Cabral, Alamgir Karim, Eric J. Amis Polymers Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland, 20899-8542, USA Fax: þ1 301 9754924; E-mail: alexander.norman@nist.gov Received: October 27, 2003; Revised: November 5, 2003; Accepted: November 6, 2003; DOI: 10.1002/marc.200300239 Keywords: combinatorial; diblock copolymers; phase behavior; SAXS; WAXS Introduction High throughput scattering methods were employed to study phase behavior over a concentration gradient to probe the vesicle structure of a diblock copolymer in water. Com- binatorial approaches use composition libraries, either continuous gradients or discrete multiple samples removing the need for preparing each individual sample and reducing experimental acquisition time, since the samples do not need to be loaded individually, and no re-alignment proce- dures are required. In this work, scattering methods were chosen to study such systems, since they cover length scales ranging from a few angstroms (WAXS – Wide angle X-ray scattering) to approximately 200 nm (SAXS – Small angle X-ray scattering). Moreover, since the structure is probed in reciprocal space and the inspection volumes are large compared to the scattering units, representative statistical properties are obtained without local artifacts. In addition, this technique is nondestructive and data acquisition is rapid, typically 10 to 150 s, dependent on flux, the count rate of the detectors, and the degree of contrast. To carry out such experiments as quickly as possible, all SAXS/WAXS studies are carried out at a synchrotron source, where the flux is significantly higher than conventional laboratory sources, typically 10 11 to 10 13 photons/s, and the wave- length is monochromatic, typically 0.8 to 1.5 A ˚ . Liquid composition libraries can be prepared by three different methods. (1) A time variant device consisting of inlet and outlet channels, which different components are pumped through, to give a variation in concentration with time. [1] (2) A continuous concentration gradient, which is prepared by means of a flow coater. [2] However, this technique is only suitable for thin films, where confinement and surface attraction may modify phase behavior, and requires negligible diffusion during sampling times. It has therefore limited applicability when designing libraries for scattering experiments in the bulk. We have therefore used a (3) discrete composition gradient, consisting of a multiwell library, each well containing varying amounts of each com- ponent. By incorporating such a library into scattering Summary: We present a high throughput X-ray scattering study (SAXS/WAXS) of the formation and stability of the vesicle phase of a water soluble diblock copolymer. The vesicle shape and shell thickness were investigated as a func- tion of block copolymer concentration and temperature. We were able to establish a growth in the SAXS peak as concentration increased, indicating a greater polymer con- centration of vesicles. The effect of temperature was also investigated. Library sample of a discrete concentration gradient of EO(6)BO(11) in water. Macromol. Rapid Commun. 2004, 25, 307–311 DOI: 10.1002/marc.200300239 ß 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Communication 307 a Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.