Inner structure of adsorbed ionic microgel particles.
نویسندگان
چکیده
Microgel particles of cross-linked poly(NIPAM-co-acrylic acid) with different acrylic acid contents are investigated in solution and in the adsorbed state. As a substrate, silicon with a poly(allylamine hydrochloride) (PAH) coating is used. The temperature dependence of the deswelling of the microgel particles was probed with atomic force microscopy (AFM). The inner structure of the adsorbed microgel particles was detected with grazing incidence small angle neutron scattering (GISANS). Small angle neutron scattering (SANS) on corresponding microgel suspensions was performed for comparison. Whereas the correlation length of the polymer network shows a divergence in the bulk samples, in the adsorbed microgel particles it remains unchanged over the entire temperature range. In addition, GISANS indicates changes in the particles along the surface normal. This suggests that the presence of a solid surface suppresses the divergence of internal fluctuations in the adsorbed microgels close to the volume phase transition.
منابع مشابه
Structure and Transport of Latex Microgels in Aqueous Suspension
Cationic latex microgel particles were studied in dilute aqueous suspensions of varying ionic strengths. Static light scattering indicates a Gaussian distribution of polymer density over the length scales probed. The measured radius of gyration is up to 50% larger than that obtained from TEM measurements of dried precursor particles. This radius of gyration is observed to be weak function of io...
متن کاملDoubly crosslinked microgel-colloidosomes: a versatile method for pH-responsive capsule assembly using microgels as macro-crosslinkers.
A new family of pH-responsive microgel-colloidosomes was prepared using microgel particles as the building blocks and macro-crosslinker. Our simple and versatile method used covalent inter-linking of vinyl-functionalised microgel particles adsorbed to oil droplets to form shells of doubly crosslinked microgels (DX MGs) and was demonstrated using two different microgel types.
متن کاملImpact of single-particle compressibility on the fluid-solid phase transition for ionic microgel suspensions.
We study ionic microgel suspensions composed of swollen particles for various single-particle stiffnesses. We measure the osmotic pressure π of these suspensions and show that it is dominated by the contribution of free ions in solution. As this ionic osmotic pressure depends on the volume fraction of the suspension ϕ, we can determine ϕ from π, even at volume fractions so high that the microge...
متن کاملDrainage dynamics of thin liquid foam films containing soft PNiPAM microgels: influence of the cross-linking density and concentration.
We investigate the drainage dynamics of thin liquid foam films containing PNiPAM microgel suspensions with two cross-linking densities (1.5 and 5 mol% BIS) and at two microgel concentrations (0.1 and 1% wt). For this purpose, we use a thin-film pressure balance apparatus that can apply a controlled and sudden hydrostatic pressure on a film, and record the subsequent film thinning as a function ...
متن کاملThermodynamics of ionic microgels.
We present a theory of dilute aqueous suspensions of microgel particles. It is found that as the number of charged monomers in the polymer network composing mesoscopic gel increases, the particles undergo a swelling transition. Depending on the hydrophobicity of the polymer, this transition can be either continuous or discontinuous. Furthermore, similar to charge stabilized colloidal particles,...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Langmuir : the ACS journal of surfaces and colloids
دوره 30 24 شماره
صفحات -
تاریخ انتشار 2014