Title: Investigation of matter transport by means of PFG NMR Author: Mikuláš Peksa Department of low temperature physics Supervisor: doc. RNDr. Jan Lang, Ph.D. Assistant Supervisor: RNDr. Milan Kočiřík, CSc. (ÚFCH JH AV ČR) Abstract: Estimation of transport-structural parameters such as porosity, tortuosity and surface-to-volume ratio of pores in beds of glass beads is the main goal of this study. These parameters were estimated for 5 samples with different distributions of sizes. The second goal is to probe a possibility to use the same approach to describe the self-diffusion in water solution of LiCl confined in two porous materials based on Al2O3 and glass, respectively. The last goal is the measurement of self-diffusion of water molecules in mesoporous geopolymeric material. Its capability of water transport at long scales have been documented. The measurements of apparent self-diffusion coefficients by means of NMR spectroscopy with pulsed field gradients was major methodology of this work. Keywords: porous material, porosity, tortuosity, self-diffusion, NMR

It is well known that ions affect polymers in specific ways not solely based on electric charge, usually referred to as the Hoffmeister effect or ion specific effects. Poly(N-isopropylacrylamid) (PNIPAM) is a thermosensitive polymer with a LCST at 32℃. PNIPAM is a well studied polymer due to its similarities with denaturation of proteins in aqueous solutions. Utilizing diffusion NMR this report studied the effect different Hoffmeister anion concentrations have on the configuration of pre-transitional PNIPAM. A fractionation process was developed for PNIPAM, yielding a product of about 87 000 g/mol, used for diffusion measurements. Diffusion coefficients for PNIPAM in saline solutions ranging from 0 to 800 mM were measured for NaCl, NaClO4, NaSCN and NaI. Diffusion coefficients for PNIPAM were also measured at some concentrations of NaF, Na2SO4 and Na2CO3. Hydrodynamic radius was calculated from the diffusion coefficients. The report found a pre-transitional chain collapse of PNIPAM which increased with ionic concentrations of NaCl, NaClO4, NaSCN, NaF and Na2CO3, but not for NaI and Na2SO4. At 800 mM the hydrodynamic radius decreased with 9% for NaCl, 13% for NaClO4 and 5% for NaSCN. The hydrodynamic radius decreased with 19% at 300 mM Na2CO3 and with 10% at 400 mM NaF. There was a significant decrease in hydrodynamic radius for high concentrations of NaCl and NaClO4 but exact decrease needs to be replicated to validate the findings due to an unexpected large decrease in hydrodynamic radius already at 50 mM. Values for NaF and Na2CO3 should be replicated with internal standard to accomodate for possible precipitation of the longer polymer chains within the fraction.