Nanotechnology

The convenience of membrane-based molecular separations is widely accepted within the Bioscience industry. An intriguing application segment is the use of lab-scale ultrafiltration devices for the manipulation of macromolecules such as peptides, proteins and nucleic acids in ever-growing markets such as genomics and proteomics. Key to the performance expectations of ultrafiltration lab-scale devices is the quality, and in particular the consistency, of the media encapsulated within the device. It is essential to know that membrane cast in large linear quantities will be operationally functional at the centimeter-to-centimeter level and directly applicable to the intended lab-scale end use.

By following Quality Function Deployment (QFD) within our product development schema we have generated a proteomics application-led approach to assess media manufacturing consistency that allows direct alignment to end user Critical to Quality (CTQ) parameters. Using ultrafiltration media as an example, we will illustrate the use of an application-led mechanism to ensure consistent media production that is directly related to the intended end use. Key to our illustration will be description of the generation of a specific applications toolbox that not only enables assessment of membrane performance and consistency, but also gives indication of likely membrane operation once incorporated into a lab-scale device.

This paper deals in general with fabrics consisting of bicomponent fibers that are fractured and bonded by Hydroentangling to form micro-denier fibers. Spunbonding process using bicomponent filament technology, where two compatible polymers are extruded together to produce continuous filament webs has been discussed. This process of nonwoven fabric manufacture combined with the fiber fracturing process using Hydroentangling is discussed. In particular, this paper deals with the bonding energy requirements for modified ‘Islands-in-the-Sea’ filament cross-sections that enhance the fracturing of such filaments. This technology can be used to produce micro- and nano-fiber webs that have considerably higher surface area. Two different compatible polymer systems (Polyester/Nylon and Nylon/Polyethylene) were explored. Optimal bonding conditions for the fabrics were identified. 

This research explored two potential strategies for integrating metallic nanomaterials into synthetic and non-synthetic polymer systems. Both strategies were conceived to have minimal impact on the polymer material properties, while preventing nanoparticle aggregation and providing a covalent attachment to the polymer chains. Three model polymers were chosen for study; nylon 6,6/6 co-polymer, polyproylene and cellulose. A robust aqueous/organic nanoparticle synthesis method was modified for each specific target polymer by creating a mixed capping organic layer that defined the surface energy and solubility in the polymers while providing a method for covalent attachment to the polymers. The synthesized materials and extruded resins were characterized by DLS, UV-VIS spectrophotometry and GFAAS.

Polypropylene spunbonds are one of the highly consumed substrates in the nonwoven industry. Owing to its hydrophobic character, it has restrained usage in next-to-skin applications. New developments have taken place in the industry to enhance the comfort aspects of polypropylene. Efforts have also focused on surface treatments such as plasma. However, there is no information available in public domain on the surface changes at nanolevel of spunbonds due to functionality enhancement treatments such as plasma etching. This paper will present some new information on the changes that have taken place at nanolevel of spunbonds due to surface treatments. Atomic Force Microscopy (AFM) has been optimized to characterize the nanolevel changes in spunbonded nonwovens.  These are correlated with wettability results as well as macro level friction experiments using a standardized sliding friction apparatus. The chemical structure of the untreated and treated spunbonds has been analyzed using FTIR. The results to-date, show that oxygen gas plasma treated spunbonds have less than 0.5 microns indentations on the surface which are not very deep. One hypothesis is that, these indentations due to plasma treatment can act as pores resulting in enhanced transport of vapor giving improved comfort. In addition, AFM when optimized is capable of measuring the fiber characteristics in spunbonded fabric. As it is evident from Figure 1 the fiber diameter is roughly between 10-15 microns. Figure 2 shows the indentation due to plasma etching.