1. Can you briefly describe what you achieved in this article?  
First of all let me state that these are common achievements with my PhD student, Martin Konieczny, who has meanwhile defended his Thesis and passed his final exam with flying colours. What Martin and myself found was that if you let charged polymers of a star-like architecture be adsorbed on oppositely charged surfaces, you obtain a well-characterised variety of exactly five different adsorbed shapes. People knew, from experiments, about the (intuitive) fact that a star will lie flat on the surface when it is strongly adsorbed and `sticks' on the wall, a shape termed `starfish' configuration. But nothing was known about other possible forms. We have identified four other partially adsorbed states that are very clearly distinguishable from each other morphologically and we are now able to say under which conditions each of these states will be the stable, equilibrium shape. We were ourselves surprised to see that these morphologies are exactly five and that transitions between those seem to take place rather sharply.

2. Could you explain the significance of your article to the non-specialist?
Suppose you want to cover a surface with some soft material, like a charged polymer. If the material stands up there in a regularly curved fashion, then you have a sort of miniature lens, a microlens. Now suppose that you can change the curvature, the size and the water content of this lens at will, by turning some external knob. Low and behold, you have a switchable lens and you can focus light at varying focal points, which you can control at the microscopic level. Further, we found that you can make some of the chains stand up like antennas and you can control how many of them do so for a single star polymer and then you can also control how many of these you have on your surface. This way, one can achieve what is called "surface functionalisation", a surface covered with microscopic "hair", which has varying electric or wetting properties. We believe that we have put forward some very concrete and realistic ideas as to how you can do such kinds of things in a well-controlled way.  

3. What has motivated you to conduct this work? 
I have been working on star-branched polyelectrolytes and other soft colloids for quite a while and I have a very active interest in the properties of deformable and tunable nanoparticles. My deep motivation to study these systems is sheer curiosity. Clearly, once Martin and I started getting some results for this problem, we also thought about possible applications. However, this was not our primary goal. Science is there to ask questions that look interesting and which appear to have an answer that can be found in a reasonable amount of time. If it's fun, then you do it with excitement and drive, and at the end it might even prove useful for making some devices out of your findings or whatever people may call "useful". But for me, it is already useful and justified if it satisfies my curiosity.   

4. Where do you see this work developing in the future? 
One direction in which we have already achieved considerable progress is the investigation of complexes formed between star-shaped polyelectrolytes and spherical colloids of opposite charge. Here, we expect a rich complexation morphology, since the size- and charge ratios are additional parameters that can be varied. Another interesting possibility is to use polyelectrolytes of a different architecture, branched ones for example. Soft matter opens many ways because the molecules we use are very versatile and synthesis techniques have reached a very advanced stage. 

5. Are there any particular challenges facing future research in this area? 
Niels Bohr once said, "Prediction is very difficult, especially about the future". I can nevertheless risk a guess based on my personal taste and interests. I would think of encapsulation of smaller particles into large, soft ones as a particularly exciting challenge, in the sense that systematic studies on this phenomenon are rather lacking. Protein adsorption is an issue that is taking off with some very exciting experimental work going on and theory has to catch up here.